Vitamins and supplements have taken a beating recently -- a Dec 17 editorial published in Annals of Internal Medicine
claimed "Enough is enough: stop wasting money on vitamin and mineral supplements."Strong words! But what exactly was researched, and what does that mean for the supplements people use, and the ones they give to their pets?
Generalizations of Three Studies
The widely-publicized paper was in fact a study of other studies -- an effort to gather information from three different research projects on supplements, and provide a conclusive answer. The problem here, as many have pointed out
, is that the three studies chosen weren't the only ones, or even necessarily the best, and the conclusions drawn were perhaps pushed into a jazzy headline.
The Nitty Gritty
The first study reviewed in the paper focused on vitamins and minerals meant to reduce heart attack, stroke, or need for heart surgery*. The supplements reduced these events by 11 percent, as compared to a placebo. Because this percentage is not considered statistically significant, the Annals
paper concluded that the treatment was ineffective -- but what "not statistically significant" really means is that we can be less than 95 percent certain that the effect was real.The second study focused on cognitive brain function in men and the daily use of a low-potency multivitamin (Centrum Silver)**. The 8.5 year study found that the multivitamin had no effect. The paper failed to mention two other recent trials, however -- ones which found positive effects***.The third study was in itself a review of research examining whether vitamin and mineral supplements can prevent heart disease or cancer. Two large studies failed to find a beneficial effect to the heart disease supplements being taken. The research did find a statistically significant 7 percent reduction in cancer incidence in men, though, and interestingly, no effect in women****. Sounds like reason for more investigation to some, as opposed to a reason to announce "case closed."
What Wasn't Covered
Basically everything not mentioned above. Studying the heart health, cancer prevention, and brain function benefits of several vitamins certainly covers a lot of ground, but in the end, is only the beginning of a complex issue.Alan R. Gaby, M.D., past president of the American Holistic Medical Association cautions that
"Simply dismissing a vast body of research because the results are conflicting is not useful."
What About Supplements for Pets?
Nothing in the December study focused on vitamins and supplements specifically used for pets, like glucosamine and chondroitin
and fish oil
. Your vet is still your best resource for advice on what supplements might be beneficial to your pet.
- Glucosamine is an amino sugar naturally produced and found in pets' cartilage. It helps cartilage perform two of its main functions: lubrication and shock absorption. Chondroitin is a carbohydrate naturally produced in animal cartilage. It keeps cartilage hydrated, and also helps inhibit some of the enzymes in the joints that degrade cartilage.
- Fish oil for dogs and cats has been shown to support the health of the skin, coat, joint, kidneys, heart, and immune system. In some studies, it’s even been shown to slow the growth of cancer.
What Do You Think?
Have you found supplements useful for yourself, or your pets? Share you opinion in the comments below!
*Lamas GA, et al. Oral high-dose multivitamins and minerals after myocardial infarction: a randomized trial. Ann Intern Med 2013;159:797-804.
**Grodstein F, et al. Long-term multivitamin supplementation and cognitive function in men: a randomized trial. Ann Intern Med 2013;159:806-814.
***Walker JG, et al. Oral folic acid and vitamin B-12 supplementation to prevent cognitive decline in community-dwelling older adults with depressive symptoms - the Beyond Ageing Project: a randomized controlled trial. Am J Clin Nutr 2012;95:194-203, and Smith AD, et al. Homocysteine-lowering by B vitamins slows the rate of accelerated brain atrophy in mild cognitive impairment: a randomized controlled trial. PLoS One 2010;5(9):e12244.
****Fortmann SP, et al. Vitamin and mineral supplements in the primary prevention of cardiovascular disease and cancer: an update systematic evidence review for the U.S. Preventive Services Task Force. Ann Intern Med 2013;159:824-834.