Research Tips

February 5, 2009
Several studies found that vitamin C supplements do not prevent the common cold. Vitamin C supplementation, however, has been shown to cut the risk of catching a cold for those exposed to an extreme physical stress like running a marathon.
Cochrane Database Syst Rev. 2007 Jul 18;(3):CD000980


February 28, 2009
Before buying special dietary supplements to enhance your health and energy level, take the extra step to make sure that the product is not another form of "snake oil." A web search on the product name along with the terms "scam" or "ripoff" can bring up interesting information.
Int J Toxicol. 2003 Sep-Oct;22(5):387-90.


March 19, 2009
Large daily doses of vitamin C do not appear to prevent colds, but taking vitamin C supplements during a cold may slightly reduce the duration of cold symptoms.
Cochrane Database Syst Rev. 2007 Jul 18;(3):CD000980.


April 21, 2009
A three-year study of women over 65 found that a daily supplement with 700 IU of vitamin D reduced the odds of falling by 46 percent in the more active women and by 65 percent in less-active women. Other studies report that good vitamin D status enhances lower-body strength and coordination.
Arch Intern Med. 2006 Feb 27;166(4):424-30.


April 28, 2009
During pregnancy, even non-prescription medications, herbal products and essential oils have the potential to cause birth defects. Drugs and herbal supplements should be used only with the guidance of a physician or pharmacist.
Birth Defects Res B Dev Reprod Toxicol. 2003 Dec;68(6):505-10.


May 1, 2009
Vitamin K is beneficial for blood, bone, and cardiovascular health, but it is commonly left out of multi-vitamin supplements. Green vegetables are the main source of vitamin K in most people's diets.
Clin J Am Soc Nephrol. 2008 Sep;3(5):1504-10.


July 23, 2009
Knowing the basics of nutrition science helps to decrease a person's susceptibility to all the “snake oil” health hype that pervades the modern world.
Int J Health Serv. 2003;33(2):383-9.


November 9, 2009
Both regular exercise and adequate nutrition play essential roles in maintaining muscle. Consuming a whey protein supplement may help to improve skeletal muscle in older individuals.
Nutr Res. 2008 Oct;28(10):651-8.


November 11, 2009
As long as you consume a diet with lots of variety and adequate calories, then you should be getting an adequate amount of vitamin B6.
Institute of Medicine DRI Chapter on Vitamin B-6


December 6, 2009
Are you tired of ads for fraudulent nutrition products? File complaints about questionable products online at the Federal Trade Commission website.
Federal Trade Commission complaints


January 6, 2010
The Federal Trade Commission recommends being careful about ads for “free” dietary supplements - "just for the cost of shipping." You may receive a second “subscriber” shipment in a month and a bill on your credit card.
Federal Trade Commission


February 4, 2010
Creatine supplementation has been studied mostly for enhancing muscle strength. Researchers also found that six weeks of creatine supplementation improved short-term memory in young adult vegetarians.
Proc Biol Sci. 2003 Oct 22;270(1529):2147-50.


February 5, 2010
Research involving over 11,000 people showed that regular use of vitamin C supplementation did not prevent the common cold, but it did reduce the severity of symptoms and the length of a cold.
Cochrane Database Syst Rev. 2007 Jul 18;(3):CD000980.


March 9, 2010
A balanced diet is the ideal way to meet nutrient needs. However, people who limit specific food groups or have very low calorie needs can benefit from taking a daily multivitamin/mineral supplement.
Arch Gerontol Geriatr. 2009;49 Suppl 1:19-27.


April 1, 2010
Many herbal products are marketed to athletes with promises to boost performance despite very limited research to support these claims. The first step to quality performance is a balanced diet that meets essential nutrient needs.
Am. J. Clin. Nutr. 72:624S–636S.


April 2, 2010
Calcium-fortified foods make getting your daily calcium relatively simple. Because excess calcium can decrease the absorption of other essential minerals like iron and zinc, it might be prudent to consume only 1 calcium fortified food a day.
Br J Nutr. 1993 Mar;69(2):533-40.


April 30, 2010
Food labeling regulations change slowly despite growth in nutrition knowledge. Currently, when a food or dietary supplement label indicates 100% of the "Daily Value" for vitamin A, it actually contains just over 200% of the currently recommended intake for a woman.
Nutr Rev. 2007 Oct;65(10):425-38.


June 6, 2010
Sublingual vitamin B-12 pills designed to dissolve under the tongue are not more effective than pills that are swallowed, according to current research. However, the sublingual pills can be a good option for those who have difficulty swallowing pills.
Br J Clin Pharmacol. 2003 Dec;56(6):635-8.


July 18, 2010
Research shows that regular use of high vitamin C supplementation does not prevent the common cold. However, in people who are exposed to an extreme physical stress like running a marathon, vitamin C supplementation can cut the risk of catching a cold in half.
Cochrane Database Syst Rev. 2007 Jul 18;(3):CD000980.


July 19, 2010
Unfortunately, some non-prescription medications, herbal products, and essential oils can cause birth defects. Consequently, no drugs or herbs should be used without the guidance of a physician or pharmacist - especially during pregnancy.
Birth Defects Res B Dev Reprod Toxicol. 2003 Dec;68(6):505-10.


July 24, 2010
Zinc nasal gels have been a popular cold remedy. Unfortunately, recent research indicates that their use can damage olfactory function and result in loss of the sense of smell.
Arch Otolaryngol Head Neck Surg. 2010 Jul;136(7):673-6.


August 9, 2010
A multivitamin/mineral type of dietary supplement can make sense when calorie intake is low. This often is the case for those who are cutting calories for weight loss and for older adults who have low levels of physical activity.
J Am Diet Assoc. 2007 Aug;107(8):1322-32.


August 14, 2010
If you are thinking that a nutritional product’s claims are “too good to be true,” try conducting an Internet search using the product’s name and terms like “scam” and “ripoff.” This can yield interesting and useful information.
Int J Toxicol. 2003 Sep-Oct;22(5):387-90.


August 20, 2010
Unscrupulous sellers of nutritional products often use marketing techniques that prey on our basic fears and desires under the guise of having scientific evidence for their product. Too often the "evidence" is just contrived pseudoscience.
Creating Your Own Pseudoscience


September 13, 2010
Taking high levels of dietary supplements may be beneficial in states of nutrient insufficiency, however consuming ample amounts of a wide variety of foods is a safer route to health.
Am J Clin Nutr. 2009 May;89(5):1543S-1548S.


September 17, 2010
The safe use of a multi-vitamin/mineral supplement depends on its nutrient formulation and your overall diet. Some dietary supplements may exceed safe levels for certain nutrients; if you also eat fortified foods, you may be at greater risk of exceeding safe limits for some nutrients.
How much is too much?


October 12, 2010
If you take a fish oil supplement, don't exceed the product's dosage directions. Some studies have reported that taking excessive amounts of fish oil on a regular basis could impair immune function and increase the risk of hemorrhagic stroke due to a blood-thinning effect.
Clin Nutr. 1993 Dec;12(6):321-8.


November 2, 2010
Red yeast rice supplements are taken by many people to lower blood cholesterol levels. Unfortunately, chemical analysis of 12 commercial preparations showed that the amount of active compounds varied greatly with the highest product containing 35 times as much as the lowest. Possibly of greater concern, four products contained a liver toxin.
Arch Intern Med. 2010;170(19):1722-1727.


November 3, 2010
Vitamins in dietary supplements degrade more rapidly in a moist environment like the bathroom medicine cabinet. Store unopened vitamin supplements in the refrigerator. When ready to use, let the bottle warm to room temperature before opening and then store in a dry place at room temperature when the bottle is being opened on a daily basis.
J Agric Food Chem. 2010 Mar 24;58(6):3532-40.


November 28, 2010
Supplementation with vitamin C does not generally decrease the risk of catching a cold. However, research does indicate that vitamin C supplementation can reduce the risk of colds for people exposed to extreme physical stresses like running a marathon.
Cochrane Database Syst Rev. 2007 Jul 18;(3):CD000980.


November 29, 2010
Most of the so-called energy drinks provide real energy (calories) in the form of sugar and perceived energy from the effects of caffeine on the brain.
Drug Alcohol Depend. 2009 Jan 1;99(1-3):1-10.


January 15, 2011
If you take vitamin D supplements, select products with vitamin D3. This is important because Vitamin D2 is not as effectively utilized by the body.
J Clin Endocrinol Metab. 2010 Dec 22. [Epub ahead of print]


February 15, 2011
Ads for weight loss supplements and powders are tempting if you need to lose weight. However, research is very limited to support weight loss supplement use. There is however research that supports moving more. Remember even just standing up burns twice the calories of lying on the couch.
Nutrition Bulletin, Volume 35, Issue 4, pages 300–303, December 2010.


February 16, 2011
A recent review reports that taking zinc syrups, lozenges or tablets within a day of the onset of cold symptoms can reduce the severity and length of illness. However, don’t confuse these oral products with the intranasal zinc products that FDA warned can cause loss of the sense of smell.
Med Hypotheses. 2010 Mar;74(3):482-92.


March 5, 2011
To supplement or not to supplement? The answer is not always simple. For example, research reports that vitamin E supplementation may decrease the risk of pneumonia if you exercise regularly and don’t smoke. But, if you smoke and don’t exercise vitamin E supplementation can increase your risk of pneumonia.
Clinical Epidemiol. 2011; 2011;51-59.


April 9, 2011
Interesting new research found that some types of human gut microflora convert choline into a pro-atherosclerotic compound that increases the risk of developing cardiovascular disease in some people. Based on this, it seems best to avoid excessively high intake of supplemental choline.
Nature, 2011;472: 57-65.


April 21, 2011
A recent study on post-menopausal women found that the risk of heart attack was increased by about 20 percent in women taking calcium supplements with or without vitamin D. Additional research is needed to confirm these results and to find the right balance for maintaining both healthy bones and heart function.
BMJ. 2011;342:d2040.


June 19, 2011
ConsumerLab.com recently compared the labeled amounts of nutrients in multivitamin and multimineral supplements to the chemically analyzed amounts. Among products designed for adults, children, and pets, more than 30 percent of the products had problems.
ConsumerLab.com Multivitamin and Multimineral Supplements Review


October 11, 2011
Today's drug tests for highly competitive athletes can detect even trace amounts of banned substances. Due to contamination with illegal drugs, some dietary supplements have caused athletes to have positive drug tests.
J Sports Sci. 2007;25 Suppl 1:S103-13.


October 16, 2011
Herbal dietary supplements commonly contain natural chemicals that interact with drugs. Of special concern is the recent observation that 69 percent of the 100 most-used supplements interfere with the effectiveness of the blood thinner warfarin (coumadin).
Methods Mol Biol. 2010;663:229-40.


March 28, 2012
The cause of amyotrophic lateral sclerosis (ALS) is not known. However, a combined analysis of five large studies indicated that long-term vitamin E supplement use is associated with a reduced rate of ALS. Further study on the role of antioxidants in ALS may help to understand the cause of the condition.
Am J Epidemiol. 2011 Mar 15;173(6):595-602.


April 7, 2012
Two carotenoids, lutein and zeaxanthin, are especially beneficial for retinal health. They are found in many fruits and vegetables. Some dietary supplements provide these two compounds in the free form which makes them much better absorbed than they are from their natural sources.
J Am Coll Nutr. 2010 Dec;29(6):575-85.


April 8, 2012
According to a review of current research, providing vitamin and mineral supplementation to critically ill patients is frequently beneficial. The article does stress, however, that the type of critical illness must be considered before treating with supplementation.
Nutrition 2011;27:745-758


May 14, 2012
Some popular natural products can have powerful effects in the body. This makes them potentially very risky when they are taken with other medications. Also, discontinuing the use of these products well before most any type of surgery is absolutely essential.
Alternative and Complementary Therapies. April 2012, 18(2): 67-70.


May 22, 2012
Many people take dietary supplements in hopes that the practice will reduce the risk of developing cancer. There is evidence that some supplements may be protective, however there is much to be learned about best dosages and why some specific nutrient supplements are associated with increased cancer risk.
J Natl Cancer Inst. 2012 May 16;104(10):732-9. Epub 2012 Apr 25.


May 27, 2012
Soy isoflavone supplements have been promoted for potential cardiovascular benefits such as reducing blood pressure. However, daily supplementation with soy isoflavones over a 6-week period had no effect on blood pressure in menopausal women with high normal blood pressure.
Am J Clin Nutr. 2012 Jun;95(6):1487-94.


June 12, 2012
The recommended intakes for many vitamins and minerals are similar for men and women. However, nonpregnant women require more than twice as much iron as men and during pregnancy, iron needs are about four times as much as a man's. Iodine, zinc, folic acid and vitamin B6 needs also significantly increase during pregnancy.
Institute of Medicine Dietary Reference Intakes


June 15, 2012
Vitamin D is available as vitamin D2 and D3. Vitamin D3 is more efficiently converted to the vitamin's active forms in the body when large amounts of the vitamin are provided. However, there appears to be little difference between the forms when daily doses of each vitamin form are taken.
Am J Clin Nutr. 2012 Jun;95(6):1357-64.


June 16, 2012
Claims have been made that a common form of vitamin B12 called cyanocobalamin can be toxic at high doses because cyanide is released from the molecule. This concern is an urban myth that was disproved long ago. Cyanide is released from the vitamin, but the amount is about 1000 times less than the amount that would be toxic.
Am J Clin Nutr. 1955 Mar-Apr;3(2):129-31.


June 19, 2012
Study after study has confirmed that many people have low vitamin D status. Good vitamin D status is important to good health. However, every nutrient can become toxic if consumed at excessive levels for too long. A new study highlights that the risk of mortality increases at both low and high ends of vitamin D blood levels.
J Clin Endocrinol Metab. 2012 May 9. [Epub ahead of print]


June 25, 2012
Although the best option is to meet nutrient needs with a balanced variety of wholesome foods, there are stages of life when the proper use of dietary supplements can be important for optimal health. However, excessive use of dietary supplements has the potential to damage health.
Evid Rep Technol Assess (Full Rep). 2006 May;(139):1-117.


July 18, 2012
Vitamin D supplements are available as D2 and D3. A meta-analysis indicated that supplementation with a single large dose of vitamin D3 was more effective than D2 at raising blood levels of activated vitamin D (25-OH-D). However, there was no obvious difference between the effects of the two forms when taken daily over time.
Am J Clin Nutr. 2012;95(6):1357-1364. (Author video)


July 30, 2012
Resveratrol, a polyphenol found in red wine, may benefit cardiovascular health as proposed by the "French Paradox" theory. A single supplemental dose over 100 times the typical amount in a glass of red wine was found to increase arterial blood flow measured in the forearm.
Nutr Metab Cardiovasc Dis. 2011 Nov;21(11):851-6.


August 19, 2012
High tech chemical analysis of green tea dietary supplements indicated that these products are not a reliable way to obtain the beneficial compounds present in green tea. Although the researchers found some good green tea supplement products, most of the products had little of the key active components present, apparently because the compounds broke down during manufacturing and storage.
J AOAC Int. 2011 Mar-Apr;94(2):487-97.


August 23, 2012
With nutrition recommendations, a 'one size fits all' approach is not a good idea, especially when people are being treated for a specific health problem. A review of 12 prostate cancer clinical trials found problems with the common practice of taking calcium and vitamin D supplements. The supplements did not prevent bone loss as expected and appeared to increase the aggressiveness of the prostate cancer.
Oncologist. 2012 Jul 25. [Epub ahead of print]


September 8, 2012
Creatine is one of the favorite supplements of body builders. Concerns about creatine's toxicity have been largely dispensed with by ongoing research. Although someone with impaired kidney function should likely avoid creatine supplements, there may be some positive applications of creatine supplementation for the elderly.
Amino Acids. 2011 May;40(5):1409-18.


September 22, 2012
If you take a vitamin D supplement, you are likely to absorb more of the vitamin if you take it along with your largest meal of the day. This is likely because this meal is usually higher in fat which facilitates the absorption of fat soluble vitamins like vitamin D.
J Bone Miner Res. 2010 Apr;25(4):928-30.


October 5, 2012
Anyone knowledgeable of the U.S. labeling laws for dietary supplements can easily find illegal labels on store shelves or product websites. A small government study of 127 dietary supplements marketed for weight loss or immune system support found that 20 percent of the products had prohibited disease claims on their labels.
Office of Inspector General: US Dept Health & Human Services


November 4, 2012
Some alternative medicine practitioners promote the medicinal use of silver solutions for various purposes. These were used for antibiotic purposes prior to the discovery of antibiotics. However, silver is a heavy metal that can accumulate in the body and especially show up in the skin and make a person's skin blue in color. This change in skin color is apparently irreversible, somewhat like tattoo colors.
ACS Nano. 2012 Oct [Epub ahead of print]


November 27, 2012
Vitamin D supplements are available in two forms, vitamin D2 and D3. A comparison of these two forms found that D3 was much better at maintaining healthy blood levels of vitamin D during a 25 week test.
Br J Nutr. 2012 Jul 11:1-7.


January 17, 2013
One reason to consume colorful foods like fruits, vegetables, egg yolks, and salmon is to provide carotenoid pigments needed by the light-sensing retina in the eye. Dietary supplements that provide these carotenoids are a hot area of current research related to eye health, but much remains to be learned about proper dosage and safety.
Br J Nutr. 2012 Dec 5:1-12.


February 6, 2013
Since excess vitamin C can be converted to oxalic acid in the body, it has been speculated that high dose supplementation with vitamin C could increase the risk of oxalate kidney stone formation. A recent Swedish study that followed over 48,000 men for 12 years found that those taking a vitamin C supplement at a dose of 1000 mg per day were about twice as likely to develop kidney stones.
JAMA Intern Med. 2013. [Epub ahead of print]


February 12, 2013
Nutrient supplements may be beneficial to health when they help to maintain adequate intake of essential nutrients. However, excessive intake of nutrients has the potential to cause unintended health problems.
Linus Pauling Institute: Online Vitamin C Summary


March 14, 2013
Vitamin D supplements are available in two forms: D2 and D3. Most research indicates that the D3 form is more effective at improving vitamin D status. It is not known if there would be any value to supplementing with a combination of the two forms of vitamin D.
Am J Clin Nutr. 2012 Jun;95(6):1357-64.


April 25, 2013
All nutrients are potentially toxic at some dose, but the dosage that is potentially toxic varies greatly among the essential nutrients. A new review of vitamin E suggests that this nutrient has very low toxicity due to the way it is metabolized in the liver.
J Lipid Res. 2013 Mar 15. [Epub ahead of print]


June 4, 2013
A small study of 17 people found that glucosamine supplements, commonly taken to manage or prevent joint problems, caused eye pressure to increase significantly. Although more study of this is needed, those known to have high eye pressure or established glaucoma most likely should not be taking glucosamine supplements.
JAMA Ophthalmol. 2013;():1-3.


June 18, 2013
Adequate iodine intake is required for normal thyroid function and needs increase in women during preconception, pregnancy, and lactation. Generally, a normal multivitamin/mineral supplement containing 150 mcg iodine daily will meet these needs along with dietary intake. The American Thyroid Association advises against the daily ingestion of iodine and kelp supplements containing more than 500 micrograms of iodine.
American Thyroid Association Press Release


June 26, 2013
Looking for information about a dietary supplement? Now there is a one-stop-shop website produced by the NIH Office of Dietary Supplements. Any information that is on the product label of about 17,000 dietary supplement products is available in this new database that is designed to meet the needs of consumers and researchers as well.
Dietary Supplement Label Database


July 19, 2013
DMAA, also known as 1,3-dimethylamylamine, methylhexanamine or geranium extract, is an ingredient found illegally in some dietary supplements. It often is promoted as a “natural” stimulant. Ingestion of DMAA can elevate blood pressure and lead to cardiovascular problems ranging from shortness of breath and tightening in the chest to heart attack. FDA action led to a voluntary destruction of over 8 million dollars worth of the Jack3d and OxyElite Pro products that contained DMAA.
FDA Public Advisory


July 28, 2013
The U.S. Food and Drug Administration posted warning letters to 15 companies that market unapproved supplements, creams and other so-called diabetes treatments. The products contain harmful ingredients or are otherwise unsafe. Some products even contain unlabeled diabetes drugs that require prescriptions.
FDA Consumer Warning on Fraudulent Diabetes Products


August 5, 2013
In the U.S. many people take strontium citrate supplements for the treatment or prevention of osteoporosis. Extensive European study of a similar strontium compound found it to be an effective treatment. However, based on recent evidence that strontium slightly increases the risk of heart attack, it is currently recommended that strontium not be used by people with any form of heart or blood vessel disease.
Medicines and Healthcare Products Regulatory Agency


August 11, 2013
The Aristolochia genus includes over 500 species of plants, many of which have a history of use in traditional herbal medicine. Examples of common names for these plants include birthworts, mercury goosefoot, pipevines, pelican flower, rooster flower, smearwort, Virginia snakeroot, and Dutchman pipes. These herbs contain the powerful carcinogen aristolochic acid that is now known to cause urinary tract cancers. Although banned in most countries for use in herbal preparations, some of these herbs still show up in herbal products.
Sci Transl Med. 2013 Aug 7;5(197):197ra101.


October 23, 2013
According to a new study using DNA barcoding to identify herbal ingredients, when it comes to herbal products available in the U.S. and Canada, you have about a 50/50 chance of getting what is on the product label. About 60 percent of the products tested had labels that were incorrect and some products had none of the labeled herb in the product.
BMC Medicine, October 2013. [Epub ahead of print]


November 1, 2013
Supplementation with three B vitamins (folate, B-6, and B-12) can help to reduce blood levels of a cardiovascular disease risk factor known as homocysteine. A new review of 14 studies found that supplementation with these vitamins reduced the statistical risk of having a stroke by about seven percent.
Neurology. 2013 Oct 8;81(15):1298-307.


November 4, 2013
During and after high intensity strength exercise, blood testosterone levels generally increase in men. A recent study found that two weeks of supplementation with soy protein isolate reduced this testosterone increase in comparison to the response following supplementation with whey protein isolate.
J Am Coll Nutr. 2013;32(1):66-74. doi: 10.1080/07315724.2013.770648.


November 11, 2013
Women often are recommended to take an iron supplement during pregnancy to meet increased iron demands. Some women experience negative gastrointestinal side-effects from daily iron supplementation. A study conducted in a rural VietNam setting found that taking the supplement twice weekly, instead of daily, provided similar benefits to both infant and mother.
PLoS Med. 2013 Jun;10(6):e1001470.


December 18, 2013
The dietary supplement industry is big business and many people taking dietary supplements may not need them. However, it is difficult to conduct definitive studies with a shotgun approach to see if taking a multi-vitamin/mineral supplement for years will reduce health problems in people that may already be meeting their nutrient needs with an adequate diet. If someone's diet is deficient in a nutrient, taking an appropriate supplement can prevent or reverse serious health problems.
Ann Intern Med. 2013;159(12):850-851-851.


January 2, 2014
If you are confused by reports on the value of vitamin supplements, you can blame flawed research designs according to a new study of past research on vitamin C. The authors point out many problems such as the failure to assess initial vitamin status of participants in supplementation studies.
Nutrients 2013, 5(12), 5161-5192.


February 3, 2014
An evaluation of dietary supplements sold for infants and children found that the levels of some vitamins were significantly greater than recommended levels. In products designed for 1 to 3 year old children, the average amounts of vitamin A and niacin exceed the tolerable upper intake levels set by the Institute of Medicine.
JAMA Pediatr. January 27, 2014. [Epub ahead of print]


February 14, 2014
A 2-gram supplement of the amino acid tyrosine was found to enhance reactions that help you to stop - like stopping a car. The popular articles about this study suggest eating spinach or eggs to get this effect. However, according to USDA food data, to get the amount of tyrosine used in the study, you would need to consume about 5 cups of cooked spinach or 8 eggs. Don't try this at home . . . or anywhere else.
Neuropsychologia. 2014 Jan 13. [Epub ahead of print]


February 20, 2014
A study of 42 people suffering from hives, a type of skin rash with red, itchy bumps, found that symptoms were significantly reduced by taking a vitamin D3 supplement of 4000 IU per day for 12 weeks. Those taking 600 IU per day had no improvement. Interestingly, there was no association between vitamin D blood levels and symptoms.
Ann Allergy Asthma Immunol. 2014 Feb 5. [Epub ahead of print]


February 25, 2014
A randomized, double-blind, placebo-controlled trial provided a multivitamin supplement or placebo to 14,641 US male physicians 50 years of age or older. They were followed for an average of 11.2 years. In those taking the multivitamin, there was a modest and significant reduction in the risk of developing a cataract. The multivitamin consisted of Centrum Silver plus additional vitamins E and C.
Ophthalmology. 2014 Feb;121(2):525-34.


March 1, 2014
A large supplementation study on selenium and vitamin E concluded that selenium supplementation did not reduce the risk of prostate cancer in men with low selenium levels and it increased risk in those with high selenium levels. The study also found that vitamin E should not be taken in levels above recommended daily intakes.
J Natl Cancer Inst. 2014 Feb 22. [Epub ahead of print]


March 18, 2014
A 24-week study of glucosamine supplementation of people with mild to moderate pain in one or both knees found that there was no difference between the supplement and a placebo pill.
Arthritis & Rheumatology.March 11, 2014. [Epub ahead of print]


March 19, 2014
Daily supplementation of postmenopausal women for two years with 1000 mg of calcium and 400 IU of vitamin D3 benefited blood lipid levels by increasing HDL cholesterol, lowering LDL cholesterol, and reducing triglycerides. The researchers concluded that these health benefits were primarily due to improved vitamin D status.
Menopause. 2014 Mar 3. [Epub ahead of print]


March 24, 2014
It has been proposed that vitamin E helps to prevent prostate cancer. Supplementation trials, however, have provided inconsistent evidence for this. A new study indicates that genetic variations can affect vitamin E handling in the body and vitamin E levels in the blood. Consequently, future studies should measure both vitamin E consumption and blood levels of the vitamin.
J Nutr. 2014 Mar 12. [Epub ahead of print]


April 8, 2014
Mix equal parts fact and fiction and you have the simple recipe for profitable sales in the dietary supplement business. It can be challenging to sort out fact from fiction, so seek guidance from knowledgeable health professionals when you are looking for reliable sources of dietary supplements.
N Engl J Med 2014; 370:1277-1280.


May 31, 2014
The fish oil omega-3 fatty acids EPA and DHA function in the body in ways that are expected to benefit cardiovascular health. Although this may be the case in general, taking fish oil supplements after the age of 50 did not show any significant benefit in a study of over 4000 people.
JAMA Intern Med. 2014 May 1;174(5):763-71.


June 7, 2014
Step one in nutrition is meeting essential nutrient needs. Most nutritionists agree that the ideal way to accomplish this is by eating the amounts and types of foods that provide all of these nutrients in adequate amounts. Unfortunately, many people do not consume diets that are adequate to meet recommended amounts of several key nutrients. For these people, a nutritional supplement can be very important for long term health.
Ann Intern Med. 2014 Jun 3;160(11):807


June 27, 2014
A one-year study of older women found that taking 200 mg per day of supplemental calcium (with about 1000 mg/day from diet) resulted in excessively high blood calcium in about one out of ten women and excessive urinary calcium levels in almost one out of three. Since this increases a variety of health risks, especially kidney stones, the researchers suggested that women should have blood and urine calcium levels checked prior to and three months after starting calcium supplementation. The vitamin D the women were also taking did not appear to affect the calcium levels.
Menopause. 2014 Jun 16. [Epub ahead of print]


June 29, 2014
Drug induced liver injury also can be caused by some common herbal supplements. For example, green tea extract is known to cause liver injury when consumed in excess. To put this into perspective, the average cup of green tea has 50-150 mgs of the active catechin components, whereas some green tea extract pills contain over 700 mg. Taking this dose multiple times a day can be dangerous.
Am J Gastroenterol. 2014 Jun 17. [Epub ahead of print]


July 1, 2014
With all the vitamin and mineral fortified foods such as a wide variety of breakfast cereals for kids, children can have nutrient intakes from foods alone that exceed the Tolerable Upper Intake Level (UL) for several nutrients. Add one of the popular children's multivitamin/mineral supplements and the risk of nutrient toxicity can be quite high. Read labels to see how things add up and compare the totals to the established UL values.
How Much is Too Much?


July 6, 2014
An extensive review was conducted of medical records that included prescribing the herbal antidepressant drug St. John's Wort. It was found that in almost one out of three cases, patients also were taking drugs that have serious interactions with this herbal supplement. The researchers stress that this type of herbal product should provide precautionary drug interaction information in product packaging for use by both patients and physicians.
J Altern Complement Med. 2014 Jun 23. [Epub ahead of print]


July 20, 2014
Vitamin E, Selenium and Prostate: A large double-blind, placebo-controlled study found that daily supplementation with selenium (200 micrograms) and/or vitamin E (400 IU) significantly increased the risk of developing prostate cancer. Men who had the highest vitamin E status at the beginning of the study were more likely to develop prostate cancer if they were taking the selenium supplement (in the form of selenomethionine).
Cancer Prev Res (Phila). 2014 Jun 24. [Epub ahead of print]


August 3, 2014
B Vitamins & Alzheimer Disease: A population-level study concluded that B vitamin supplementation to lower blood levels of a compound called homocysteine was not associated with a reduced risk of the cognitive decline typical of Alzheimer Disease. However, it should be kept in mind that the symptoms of vitamin B12 deficiency are very similar to those observed in the development of Alzheimer disease. Thorough testing of vitamin B12 status is highly recommended in cases of cognitive decline.
Am J Clin Nutr. 2014 Jun 25;100(2):657-666. [Epub ahead of print]


August 8, 2014
High dose niacin supplementation has been used as a treatment for lowering "bad" LDL cholesterol and raising the "good" HDL cholesterol in people with cardiovascular disease. Recent research, however, indicated that niacin supplementation did not reduce heart attack or stroke rates compared with a placebo. Also, niacin had some serious side effects in some people such as liver problems, excess infections, excess bleeding, gout, loss of control of blood sugar for diabetics and the development of diabetes in people who didn't have it when the study began.
N Engl J Med 2014; 371:271-273.


August 13, 2014
Even nutrients can be toxic in excess. The Institute of Medicine has established upper limits for the intake of nutrients most likely to cause problems when consumed in excessive amounts for too long. For most nutrients it takes months or years of excessive intake for noticeable problems to manifest. Nutrients of most concern include vitamins A, B-6, and D as well as calcium, iron, zinc, selenium and copper.
How much is too much?


August 22, 2014
Magnesium: It has been estimated that over 75 percent of women older than 65 years consume significantly less than the Recommended Dietary Allowance (RDA) for magnesium. A recent study of older women found that taking a 300 mg per day magnesium supplement significantly improved responses to a 12-week exercise program in comparison to women in the same program that did not take the supplement. Foods rich in magnesium include most fish, beans, most green vegetables, and nuts.
Am J Clin Nutr. 2014 Jul 9. [Epub ahead of print]


August 30, 2014
Krill oil supplements often are marketed as being superior to fish oil for providing essential omega-3 fatty acids. A new study comparing these two marine oils found that there is no significant difference between the two oils in their effects on blood levels of omega-3 fatty acids. The main difference between the oils is that krill oil contains a colorful antioxidant called astaxanthin.
Lipids Health Dis. 2014 Aug 26;13(1):137. [Epub ahead of print]


September 10, 2014
A study of people diagnosed with liver injury attributed about 20 percent of the cases to the use of a variety of herbal dietary supplements, especially the types marketed to bodybuilders. It is important to consider herbal products to be comparable to drugs and to use them with caution.
Hepatology. 2014 Jul 12. [Epub ahead of print]


September 23, 2014
Cataracts are cloudy areas in the lens of the eye and often develop in older individuals. Although oxidative damage may play a role in the development of cataracts, a five years study of over 11,000 men found that supplementation with the antioxidant nutrients vitamin E and selenium did not reduce the incidence of cataracts.
JAMA Ophthalmol. 2014 Sep 18. [Epub ahead of print]


October 3, 2014
Turmeric and Brain Health: A rat study found that a specific compound isolated from turmeric promoted the proliferation of neural stem cells in parts of the brain. Consequently, this compound may prove to be helpful in the prevention of dementias like Alzheimer's disease. However, this does not suggest that taking turmeric or curcumin supplements is safe or beneficial due to other potentially toxic compounds in these spice components.
Stem Cell Res Ther. Sept 2014;5(4):100.


October 10, 2014
Winter-related Dermatitis in Children: Some children have a tendency to develop eczema (atopic dermatitis) during winter months. A study conducted with children in Mongolia found that vitamin D supplementation significantly reduced this skin condition. Due to the limited sun exposure during winter months in Mongolia, the children likely had vitamin D deficiency during the winter season.
Br J Dermatol. 2008 Jul;159(1):245-7.


October 30, 2014
Resveratrol and Bone Health: In just four months, middle-aged obese men who were taking high-dose resveratrol supplements (500 mg/day) had a significant increase in bone mineral density at the spine and elevated levels of a key biochemical marker of bone formation. Resveratrol is found naturally in red grapes and some types of nuts.
J Clin Endocrinol Metab. 2014 Oct 16. [Epub ahead of print]


November 8, 2014
Resveratrol Supplements and Exercise: Resveratrol supplementation (150 mg/day) of men during a 4-week period of low volume, high intensity interval training impaired some of the usual responses to exercise. Interestingly, this relatively high dose of resveratrol (roughly the amount in 300 6-ounce glasses of red wine) blunted the usual training-induced increase in the body's production of an antioxidant enzyme known as superoxide dismutase-2.
Appl Physiol Nutr Metab. 2014 Nov;39(11):1305-13.


November 28, 2014
Antioxidant Vitamins and Exercise: Exercise creates oxidative stress on muscles. However taking supplements of the antioxidant vitamins C and E does not help and instead prevents some of the desired muscle adaptations to strength training.
J Physiol. 2014 Nov 10. [Epub ahead of print]


December 3, 2014
Bariatric Surgery and Vision: Bariatric surgery patients generally need to take vitamin and mineral supplements because of reduced food intake and impaired absorption of nutrients. Failure to take appropriate supplements could lead to vision problems among other potential health problems.
Obesity Surgery. 26 Nov 2014. [Epub ahead of print]


December 14, 2014
Vitamin C and Lung Function During Exercise: Vigorous exercise triggers an acute narrowing of the airways (exercise-induced bronchoconstriction) in about 10 percent of the general population, and in 90 percent of asthmatics. A review of recent studies indicates that taking 500 to 2000 milligrams of vitamin C prior to exercise significantly reduces bronchoconstriction and related symptoms.
Allergy Clin Immunol Int, doi:10.1186/1710-1492-10-58 ePub 27 November 2014.


December 21, 2014
Vitamin E and Pneumonia: Vitamin E supplementation of older mice, with a dose comparable to 200 IU in a human, significantly enhanced immune function and resistance to bacterial pneumonia infection in comparison to mice consuming a normal amount of vitamin E. It will be interesting to see if vitamin E supplementation provides similar benefit to older humans.
J Immunol. 2014 Dec 15. [Epub ahead of print]


December 29, 2014
Vitamin C and Colds: An updated review of vitamin C supplementation found that taking vitamin C does not reduce the risk of catching a cold. However, there is some evidence that vitamin C supplementation may reduce the duration and severity of a cold.
Cochrane Database Syst Rev. 2013 Jan 31;1:CD000980.


December 30, 2014
Fat and Vitamin D Absorption: Vitamin D is one of the fat soluble vitamins that are absorbed better when consumed with a meal containing fats or oils. A new study found that blood levels of vitamin D were 32 percent greater when a vitamin D supplement was taken with a fat-containing breakfast compared to a fat-free breakfast.
J Acad Nutr Diet. 2014 Nov 17. [Epub ahead of print]


January 13, 2015
Vitamin Supplements and Stomach Cancer: A large meta-analysis type of study found that moderate dose supplementation with nutrients like vitamins A, C, and E was associated with a reduced risk of developing stomach cancer. However, supplementation with higher doses, such as those exceeding the tolerable upper intake levels, was associated with an increased risk.
PLoS One. 2014 Dec 30;9(12):e116060.


January 16, 2015
Iron Supplementation and Omega-3 Fatty Acids: Iron supplementation has been observed to sometimes worsen infectious diseases such as malaria and tuberculosis. A study conducted with 926 iron deficient South African children (8 to 10 years old), found that iron supplementation with 50 milligrams of iron per day improved iron status and did not increase illness in children if they also took a supplement of the long-chain omega-3 fatty acids DHA and EPA (the type found in fish oils).
Am J Clin Nutr. March 2015. [Epub ahead of print]


February 21, 2015
Multivitamin-Multimineral Supplements: Many Americans take multivitamin-multimineral supplements. A new study found that women who took this type of supplement for three or more years were significantly less likely to die of cardiovascular disease
J. Nutr. March 1, 2015. [Epub ahead of print]


March 24, 2015
Safe Vitamin D Levels: There has been an abundance of research linking low vitamin D status to a variety of health issues. Recent research evaluating over 247,000 Danes now points to health issues with too much vitamin D as well. A safe range for vitamin D blood levels is currently thought to be between 50 and 100 nmol per litre. The authors recommended the goal for vitamin D should be 70 nmol per litre based on their data.
J Clin Endocrinol Metab. 2015 Feb 24:jc20144551. [Epub ahead of print]


April 14, 2015
Muscle-building Supplements and Cancer: Athletes are especially open to trying anything that promises to enhance performance. However, a new study raises some cautions about links between muscle-building supplement use and testicular cancer. The risk appears to be greater in those who took these types of supplements when they were younger. Much more needs to be learned about what components of these supplements may triggering this cancer risk.
Br J Cancer. 2015 Mar 31;112 Suppl:1247-50.


April 16, 2015
Supplement Quality: Responsibility for the control of the quantity and quality of ingredients in dietary supplements rests primarily on the manufacturers of these products. Consequently, the "buyer beware" aspect of shopping for supplements is a significant concern. Larger companies generally have tighter quality control measures. Some organizations like ConsumerLab.com test products independently to confirm that products contain what they say and are free of common contaminants.
Dietary Supplement Popularity, Quality, Safety, and Efficacy


April 30, 2015
Illegal Stimulant in Supplements: Ever since the herbal stimulant ephedra was banned in 2004, the supplement industry has been seeking a reasonable substitute. One of the latest tries is the addition of DMBA (1,3-Dimethylbutylamine). However, FDA considers DMBA to be an untested drug, which makes it illegal in a dietary supplement.
FDA. April 28, 2015. DMBA in Dietary Supplements.


May 16, 2015
An elevated blood level of homocysteine is considered to be a risk factor for the development of cardiovascular disease. Taking a daily multi-vitamin with vitamins B6, B12, and folate can help to reduce homocysteine.
Arch Latinoam Nutr. 1997 Jun;47(2 Suppl 1):9-12.


June 19, 2015
Dietary Supplements and Cancer: Various studies have linked dietary supplement use with both increased and decreased risk of developing various cancers. Possibly part of the reason for this discrepancy is that people who develop a health problem such as cancer often start taking supplements to improve their health. To minimize health risks, take dietary supplements in moderation and always consult your pharmacist about possible interactions with other medications you are tkaing.
Br J Nutr. 2015 Jun 16:1-11. [Epub ahead of print]


June 23, 2015
Vitamin D and Crohn's Disease: Crohn's disease is a chronic inflammatory gastrointestinal condition that can affect any part of the gastrointestinal tract. A small study of 27 Crohn's disease patients in remission found that those taking 2000 IU of vitamin D per day were less likely to experience a return of signs of the condition than those taking a placebo supplement.
United Euro Gastro J. June 2015;3(3):294-302.


July 8, 2015
Omega-3 Fatty Acids and Muscle: Loss of muscle mass is common in older people. Adequate protein in the diet and regular exercise both help to counter this loss. In addition, a new study found that six months of daily supplementation with fish oil (providing the amount of omega-3 fatty acids in a couple servings of salmon) increased thigh muscle slightly, along with the strength of various muscles, compared to a control group taking a placebo supplement.
Am J Clin Nutr. 2015 Jul;102(1):115-22.


August 4, 2015
Warning on Homeopathic Product: Homeopathic solutions called nosodes are ultradiluted solutions of diseased tissue, pus, blood, or excretions from a sick person or animal. Some homeopaths and naturopaths sell these products to their patients. Health Canada requires these products to include the statement that they are neither a vaccine nor an alternative to vaccination, have not been proven to prevent infection, and that Health Canada does not recommend its use.
Paediatr Child Health. 2015 May;20(4):219-22.


August 17, 2015
Adulterated Supplements: Many dietary supplements, especially those from smaller companies, have been found to be spiked with a variety of drugs. This illegal practice frequently occurs without detection. However, scientists are working out a variety of new technologies to simplify the testing products for these contaminants.
J Agric Food Chem. 2015 Jul 31. [Epub ahead of print]


August 25, 2015
Milk Protein Component and Gut Health: A component of whey protein called glycomacropeptide (GMP) has been used in diet formulations for the nutritional management of phenylketonuria (PKU) - a genetic condition that requires low dietary levels of the essential amino acid phenylalanine. New research with a mouse model indicates that GMP has beneficial prebiotic effects that produce positive changes in the lower intestinal microbiota. Further study on GMP's potential benefits for a variety of human conditions may prove to be valuable.
Am J Physiol Gastrointest Liver Physiol. 2015 Aug 6. [Epub ahead of print]


November 9, 2015
Iron Supplementation: Taking an iron supplement triggers a significant increase in a compound called hepcidin which greatly reduces the absorption of the next dose of iron - especially when the dose is high. Based on this, it appears that taking an iron supplement once every 48 hours may be more effective than once every 24 hours. Further research is needed to prove this.
Blood. 2015 Oct 22;126(17):1981-9.


November 25, 2015
Vitamin D and Winter: As sun exposure declines during winter months, the need for dietary and/or supplemental sources of vitamin D increases. Vitamin D deficiency increases the risk for cardiovascular disease along with other conditions such as metabolic syndrome and depression.
Br J Nutr. 2015 Nov 20:1-9. [Epub ahead of print]


December 6, 2015
Rights Against Fraudulent Nutrition Products: Are you tired of ads for fraudulent nutrition products? File complaints about questionable products online at the Federal Trade Commission website.
Federal Trade Commission Complaints


January 29, 2016
Oxidized Omega-3 Supplements: The highly unsaturated omega-3 fatty acids in fish or plant oil supplements are highly susceptible to oxidation when products are not produced properly. Oxidation reduces the effective level of omega-3 fatty acids in a product and gives it a bad smell and taste. At this time, it is not clear if the oxidized fatty acids have a significant adverse effect on health.
J Nutr Sci. 2015 Nov 4;4:e30.


March 15, 2016
Nutritional Supplement for Hearing Loss: Using a mouse model to study a type of hearing loss seen in children with a specific genetic mutation, researchers found that supplementation with beta carotene (precursor to vitamin A), vitamins C and E and magnesium helped to slow progression of their hereditary deafness. However, the same supplements given to mice with a slightly different mutation made the condition worse.
Scientific Reports, 2016; 6: 22690.


March 31, 2016
Multivitamin Supplements and Pregnancy: A study of 344 pregnant women found those who took multivitamin supplements prior to conception and during pregnancy had a substantially reduced risk of having a miscarriage. This was especially apparent in women over age 35.
Fertil Steril. 2016 Mar 22. [Epub ahead of print]


April 19, 2016
Banned Substance in Supplements: Although not approved for use in dietary supplements, the drug oxilofrine was found in several "fat-burner" supplements. It was listed in the label ingredients as methylsynephrine, another name for the drug. Some may confuse this with a natural compound from bitter orange called synephrine that is a legal supplement ingredient. Oxilofrine stimulates heart function and increases blood pressure like its chemical cousin ephedrine.
Drug Test Anal. 2016 Apr 7. [Epub ahead of print]


May 3, 2016
Supplements and Depression Treatment: A new study reviewed 40 studies on taking specific dietary supplements in conjunction with antidepressant medications. They found evidence that supplementation with SAMe, methylfolate (a form of folic acid), omega-3 fatty acids (specifically EPA or ethyl-EPA), and vitamin D all have the potential to enhance drug treatment of depression. One common nutrient deficiency known to contribute to depression, iron deficiency, was not considered in the study.
Am J Psychiatry. 2016 Apr 26:appiajp201615091228. [Epub ahead of print]


June 10, 2016
Vitamin D and Gut Microbes: Most studies on intestinal microbial populations analyze the bacterial populations in the contents of the lower intestine (colon) or from the stool. A new study on the effects of vitamin D supplementation sampled contents of the intestinal tract form the stomach, small intestine, the colon, and the stool. They found that vitamin D supplementation changed and improved the bacterial composition only in the upper or small intestine.
European J Nutr. 2016;55(4):1479–1489.


July 22, 2016
Antioxidant Supplements: Oxygen, of course, is required for life. However, some theories of disease suggest that various chemical reactions in the body involving oxygen create oxidative stress. It has been proposed that this oxidative stress may trigger certain diseases. Although taking antioxidant supplements may seem like the solution, these supplements may actually worsen some disease states by impairing beneficial oxidation reactions such as those involved in defense mechanisms of the immune system. Maintaining good health always seems to be a balancing act.
Br J Pharmacol. 2016 Jul 18. [Epub ahead of print]


August 5, 2016
Fish Oil Supplement and Muscle Soreness: The first bout of a new exercise often causes muscle soreness that occurs a day or two after the exercise. This is known as delayed onset muscle soreness (DOMS). A recent study found that women who took a fish oil supplement (containing a total of 3.6 g/d of the omega-3 fatty acids EPA plus DHA) experienced significantly less symptoms and biomarkers of DOMS. The U.S. Food and Drug Administration cautions against consuming EPA and DHA in excess of 3g/d due to the risk of increased bleeding time. Consequently, long term use of this dose may not be safe.
J Diet Suppl. 2016 Jul 21:1-12.


August 23, 2016
Calcium Supplements and Dementia: Adequate calcium intake is clearly important for maintaining healthy bones. However, there is developing evidence that it is likely best to meet calcium needs with foods rather than supplements. A new study that needs support from future research found that older women taking calcium supplements were more likely to develop dementia, especially if they already had signs of cerebrovascular disease.
Neurology. 2016 Aug 17. [Epub ahead of print]


October 13, 2016
Calcium Supplements and Heart Health: A new study on over 2700 people found that high total calcium intake (food and supplements combined) was associated with a decreased risk of coronary artery calcification, especially when the high calcium intake was not from supplement use. In contrast, calcium supplement use was associated with increased risk of coronary artery calcium accumulation.
J Am Heart Assoc. 2016 Oct 11;5(10). pii: e003815.


October 29, 2016
Red Yeast Rice and Safety Concerns: It has been known for some time that red yeast rice supplements taken to lower blood cholesterol levels may also contain various toxins. Caution needs to be taken when using these supplements.
J Clin Lipidol. 2013 Mar-Apr;7(2):117-22


October 31, 2016
Eye Supplements: Dietary supplements containing lutein (a colorful compound found naturally in some vegetables and fruits) is commonly recommended for the prevention or treatment of vision loss from age-related macular degeneration. However, based on a recent case study report, more than the usually recommended amount (10 mg per day) may be excessive and may potentially impair vision.
JAMA Ophthalmol. October 27, 2016. [Epub ahead of print]


January 11, 2017
Valerian and Low Blood Sodium: Two cases of hyponatremia (life-threatening low blood sodium) have been linked to excessive thirst caused by the herbal remedy valerian root. This herb is typically taken to aid with sleep, anxiousness, ADHD, and headaches. It is important to remember that herbs contain naturally occurring chemicals that have the same dangerous potential as prescription drugs.
BMJ Case Rep. 2016 Sep 28;2016. pii: bcr2016216348


February 28, 2017
Aspirin Alternative: Many people take aspirin to reduce the tendency of blood platelets to aggregate and form a clot that blocks blood flow through an artery. A new European product made from a special extract of tomatoes (Fruitflow®) promises to provide protection similar to aspirin without the risks of internal bleeding that come with aspirin use.
Eur J Nutr. 2016 Jul 7. [Epub ahead of print]


March 7, 2017
Herbal Medications and Heart Disease: Researchers reviewed the 10 most commonly used herbal medications for cardiovascular disease. Their use is so common that the researchers urge physicians to learn about issues related to their use such as possible indications for use, biological functions, clinical data, interactions with drugs, and safety concerns.
J Am Coll Cardiol. 2017 Mar 7;69(9):1188-1199. doi: 10.1016/j.jacc.2016.11.078.


March 17, 2017
Vitamin E: Most people do not consume recommended amounts of vitamin E. This appears to be especially the case in overweight people with metabolic syndrome. In most people's diets, vegetable oils are the major source of vitamin E. However due to possible oxidation of vitamin E, these oils are not always reliable sources. Moderate use of supplemental vitamin E is a reasonable option, especially for those with metabolic syndrome.
Am J Clin Nutr. 2017 Mar;105(3):571-579.


March 30, 2017
Vitamin D and Cancer: A study of postmenopausal women found that those taking vitamin D and calcium supplements did not have a statistically significant difference in the risk of developing cancer compared to those taking a placebo. However, blood levels of vitamin D were significantly lower in women who developed cancer during the 4-year study. This suggests that factors other than vitamin D intake affect vitamin D status. For example, it is known that iron deficiency impairs vitamin D metabolism, but few studies on vitamin D account for iron status of their participants.
JAMA, 2017; 317 (12): 1234 DOI: 10.1001/jama.2017.2115


April 24, 2017
Air Pollution and B Vitamins: After taking fairly high doses of three B vitamins, folic acid (2.5 mg/day), vitamin B6 (50 mg/day), and B12 (1 mg/day), for four weeks, human volunteers exposed to air pollution had less adverse physiological responses as measured by heart function changes and white blood cell counts. Long term intake of these B vitamins at these doses could potentially have adverse effects. Further studies are required to confirm this study and to evaluate the effect of longer duration of supplementation.
Sci Rep. 2017 Apr 3;7:45322.