DIETARY SUPPLEMENTS—DO THEY WORK?
I take a variety of bottled vitamin and mineral supplements every day. And you probably do too. We take supplements to make up for what we think might be missing in our diets and we hope they’ll also help prevent disease. But do they actually aid us or are we just wasting our money?
Over time, I’ve added on or dropped this or that supplement depending on what I read in magazine or online articles. For instance, I’ve dropped glucosamine because I read it might adversely affect eyesight in seniors and fish oil because it probably has no benefits. And I’ve added on Vitamin K because I read it helps transport calcium.
Still, I’d never really looked at supplements in general, so I began checking online for credible information. Here are some observations and recommendations from a Harvard Medical School article titled Dietary supplements: Do they help or hurt?
The Excitement Over Supplements
Getting our nutrients straight from a pill sounds easy, but supplements don’t necessarily deliver on the promise of better health. Some can even be dangerous, especially when taken in larger-than-recommended amounts.
We’ve heard a lot of encouraging news about supplements. A series of studies hailed vitamin D as a possible defense against a long list of diseases, including cancer, diabetes, depression, and even the common cold. Omega-3 fatty acids have been touted for warding off strokes and other cardiovascular events. And antioxidants such as vitamins C and E and beta carotene were seen as promising silver bullets against heart disease, cancer, and even Alzheimer’s disease.
Here’s the big caveat: many of those exciting supplement studies were observational—they didn’t test a particular supplement against a placebo (inactive pill) in a controlled setting. The results of more stringent randomized controlled trials haven’t yielded the same good news.
“Often the enthusiasm for these vitamins and supplements outpaces the evidence. And when the rigorous evidence is available from randomized controlled trials, often the results are at odds with the findings of the observational studies,” explains Dr. JoAnn Manson, chief of preventive medicine at Brigham and Women’s Hospital, professor of medicine at Harvard Medical School, and principal investigator of a large randomized trial known as VITAL (Vitamin D and Omega-3 Trial).
Because observational studies may not fully control for dietary factors, exercise habits, and other variables, they can’t prove whether the treatment is responsible for the health benefits. “People who take supplements tend to be more health conscious, exercise more, eat healthier diets, and have a whole host of lifestyle factors that can be difficult to control for fully in the statistical models,” Dr. Manson says.
Some supplements that were found to have health benefits in observational studies turned out, with more rigorous testing, to be not only ineffective but also risky. Vitamin E, which was initially thought to protect the heart, was later discovered to increase the risk for bleeding strokes. Folic acid and other B vitamins were once believed to prevent heart disease and strokes—until later studies not only didn’t confirm that benefit but actually raised concerns that high doses of these nutrients might increase cancer risk.
How Much of Each Nutrient Do You Need?
| Nutrient | How much do you need? | Don’t Exceed |
| Calcium | 1,000 – 1,200 mg | 2,000 mg |
| Folate | 400 mcg | 1,000 mcg |
| Iron | 8mg | 45 mg |
| Vitamin A | 700 mcg RAE* | 3,000 mcg RAE |
| Vitamin B6 | 1.5 mg | 100 mg |
| Vitamin B12 | 2.4 mcg | No established upward limit |
| Vitamin C | 75 mg | 2.000 mg |
| Vitamin D | 600 – 800 IU | 4,000 IU |
| Vitamin E | 15 mg | 1,000 mg |
*Retinol activity equivalents
How to Get Your Nutrients
We need a variety of nutrients each day to stay healthy, including calcium and vitamin D to protect our bones, folic acid to produce and maintain new cells, and vitamin A to preserve a healthy immune system and vision.
Yet the source of these nutrients is important. “Usually it is best to try to get these vitamins and minerals and nutrients from food as opposed to supplements,” Dr. Manson says.
Fruits, vegetables, fish, and other healthy foods contain nutrients and other substances not found in a pill, which work together to keep us healthy. We can’t get the same synergistic effect from a supplement. Taking certain vitamins or minerals in higher-than-recommended doses may even interfere with nutrient absorption or cause side effects.
Food Sources of Nutrients
| Nutrient | Food sources |
| Calcium | Milk, yogurt, sardines, tofu, |
| Folic acid | Spinach, lentils, beef liver |
| Iron | Oysters, chicken liver, turkey |
| Omega-3 | Salmon, sardines, flaxseed, |
| Fatty acids | Walnuts, soybeans |
| Vitamin A | Sweet potato, spinach, carrots,
cantaloupe, tomatoes |
| Vitamin B6 | Chickpeas, salmon,
chicken breast |
| Vitamin B12 | Clams, beef liver, trout, |
| Vitamin C
|
Bell peppers, strawberries,
oranges, broccoli |
| Vitamin D | Salmon, tuna, yogurt |
| Vitamin E | Wheat germ oil, almonds,
sunflower seeds, peanut butter |
3 Supplements to Take & 3 to Skip
Here are some specific recommendations from an article by Elizabeth Millard in a recent issue of Men’s Health: 3 Supplements That Actually Work—and 3 That Are Just Wasting Your Money
In some cases, supplements can fill in the nutritional gaps that can crop up even in a healthy diet, says Brianna Elliott, R.D., a coach at nutrition counseling service EvolutionEat. But there are some nutrients that you’re likely to get enough of in your regular diet, which makes supplements of them just plain unnecessary.
The trick is knowing which supplements can actually help you stay healthy—and which are likely doing nothing at all. Here’s your quick cheat sheet.
Supplement to Take: Vitamin D
Vitamin D—known as the sunshine vitamin, since you can get it from its rays—aids your body in absorbing calcium. It also helps reduce inflammation, improve mood, and boost immune function.
Many people are lacking in D, though. In particular, those in the northern part of the U.S. don’t get enough sunlight for their bodies to produce enough vitamin D naturally, says Elliott.
And that’s a problem, since vitamin D is incredibly difficult to get from food sources, she says. Vitamin D deficiency has been linked to a number of serious health issues, including depression, dementia, and heart disease.
In fact, people with low levels of vitamin D were about 20 percent more likely to experience a major cardiac event like a heart attack or heart failure, a new study presented at the American College of Cardiology Scientific Sessions found.
“The effects of low vitamin D could be cumulative,” says study author Heidi May, Ph.D., a cardiovascular epidemiologist with the Intermountain Medical Center Heart Institute. “The longer you maintain low levels, the more you might be increasing health risks.”
Supplement to Take: Magnesium
Magnesium is very important for a range of functions, from proper digestion to blood sugar control. But most American diets provide less than the NIH’s recommended amount of 400 to 420 milligrams (mg). One reason? Poor soil health compared to past centuries of agriculture, as one recent study in The Crop Journal noted. That’s because vegetables are drawing in less magnesium from the soil now, so we’d have to eat more of them to get the same amount of the mineral than before.
So even though you may be eating foods that should contain lots of magnesium—think leafy green vegetables, beans, nuts, brown rice, and whole wheat—you may not be getting as much of it as you may think, says Elliot.
Aim for about 350 mg daily in a supplement, but start low—like about 150 mg—and build up from there over a few weeks to give your digestive system time to adjust, says Elliott. Otherwise, you could risk digestive upsets like diarrhea. Look for chelated magnesium—which means the minerals have been combined with amino acids for better absorption—rather than magnesium oxide. Magnesium oxide may have more magnesium per gram, but your body doesn’t absorb it as well.
Supplement to Take: Probiotics
Probiotics—“good” bacteria that live in your gut—can improve digestion, which makes it easier for your body to absorb vitamins and minerals in your diet, says food scientist Joy Dubost, Ph.D., R.D. “Research is still emerging on the benefits of probiotics,” she says. “But we do know that they can enhance immune function.”
You can get probiotics in some food products like cultured dairy, fermented sauerkraut and kimchi, but daily supplementation can help make sure you’re getting enough—and the right kinds.
Supplement to Skip: Vitamin C
Popular belief dictates that you reach for vitamin C tablets—or foods rich in the vitamin, like oranges—to ward off a cold.
But research hasn’t actually proven it can prevent colds, though other studies have shown it can reduce the duration of cold symptoms, according to the Mayo Clinic.
Still, it’s easy to get recommended amounts without popping it in pill form.
“Most of the time, vitamin C supplements contain an excess amount of the vitamin,” says Elliott. “That means your body will end up excreting it through urine, since it’s water-soluble.”
Supplement to Skip: B-Complex Vitamins
Given the breadth of benefits of B-complex vitamins—stronger metabolism, healthy skin, better conversion of food into fuel for energy—it seems logical that popping a supplement with all 8 of them would be the way to go.
How much you need of each B-complex vitamin—including B-12, folate, pantothenic acid, riboflavin, niacin, and biotin—varies. For example, you need 1.3 mg of vitamin B6, and 2.4 mg of vitamin B12 per day.
But adding them to you supplement could be a waste, says Roussell. That’s because B-vitamins are ubiquitous in fruits, vegetables, nuts and grains, he points out. A can of tuna will get you 0.87 mg of B6 and 2.5 mg of B12, for example.
“They are everywhere, and there are no documented benefits of taking additional B-vitamins in healthy individuals,” Roussell says. Plus, the marketing claims about B-complex vitamins giving you a boost through energy drinks is just hype, he says. It’s likely the caffeine and sugar providing the energy uptick instead.
Supplement to Skip: Calcium
Calcium is a vital mineral for bone strength and nervous system function. But should the supplement be in your shopping cart? Only if you’re avoiding calcium-rich foods for some reason—say, if you’re vegan or lactose intolerant—or have a bone condition like osteoporosis or osteopenia, says Elliott.
“Calcium is important,” she says. “But it’s very easy to get through food.”
In addition to dairy products like milk and yogurt, you can get calcium in spinach, kale, bok choy, sardines, broccoli, almonds, chia seeds and salmon.
Judging Supplements
Before you take any supplements for disease prevention, it’s important to know whether the potential benefits outweigh the risks. If you’re lacking in a particular nutrient, ask your doctor whether you need to look beyond your diet to make up for what you’re missing.