A decade-long observational study of more than 30,000 people finds that certain vitamins and minerals may help extend your life and keep you from dying of cardiovascular disease—but only if you get those beneficial nutrients from foods, not supplements.
The study, published this week in the Annals of Internal Medicine, is yet another to find that taking supplemental vitamins and minerals—either individually or in multivitamins—offers no discernible benefits in terms of reducing risks of death generally or death from cardiovascular disease and cancers, specifically. Simply put, popping pills can’t take the place of eating a healthy diet—an unflashy takeaway that likely won’t please the massive, $30 billion supplement industry.
Moreover, the study didn’t just find a lack of benefits from supplements. It also found potential harms. Getting high doses of calcium (1,000 mg or more per day) from supplements—but not from foods—was linked to higher cancer mortality risks in the study. Likewise, people taking vitamin D supplements who didn’t have vitamin D deficiencies may have higher risks of all-cause mortality and death from cancers.
It’s unclear from this observational study exactly why the same vitamins and minerals had different effects based on whether they were, say, chewed from a salad or gulped in a tightly packed capsule. But, it’s likely due to the fact that our bodies are tuned by evolution to best absorb and use micronutrients at the levels and ratios found in foods.
The authors of the study—a team of nutrition experts led by researchers at Tufts University—note that:
Humans consume foods and nutrients that are highly correlated. The complex interactions among nutrients are likely to play a more important role in determining health outcomes than individual nutrients.
Take the case of calcium, for example. Earlier research suggested that regular mega-doses of calcium from the diet—maybe from late-night ice cream binges—can cause the intestines to cut back on how much of the mineral it absorbs, leading to higher calcium levels in urine (more of it gets peed out) and lower calcium levels circulating in the body. In fact, it’s very difficult if not impossible to get too much calcium from foods alone. Regularly swallowing a lot of calcium in a potent pill, on the other hand, doesn’t seem to have the same effect on intestinal absorption, leading to increased levels of circulating calcium and the potential for harms, such as constipation and increased risk of kidney stones.
Still, more than half of all adults in the US say they use supplements. Ten percent of us report using four or more each day. Given that, it’s rather important to understand the benefits and risks that they pose.
To help do that, the authors of the new study looked at data from a massive survey (National Health and Nutrition Examination Survey) taken between 1999 and 2010 from 30,899 people. More than 27,000 of those participants provided information on the supplements they took as well as inventories of the foods they recently ate. The survey also included demographic and other health data, including whether people smoked, drank, exercised, or had medical conditions, such as cancers and diabetes. The participants gave their information to trained interviewers who surveyed participants in their homes and over the telephone. The study authors then linked medical records of deaths to participants over the survey period. The study captured the deaths of 3,613 participants.
Like the general population, a little more than half of the study participants said they took supplements. Nearly 40 percent took multivitamins. The most common individual supplements people took were vitamins C, D, and E, as well as calcium and magnesium.
Based on the supplement and food reports from each participant, the researchers estimated how much of each major micronutrient participants got each day. The researchers broke the estimates down by source (food vs supplement) and noted whether they were below recommended levels, on target, or in excess.
At first glance, those taking supplements seemed to fare well—showing a reduced risk of all-cause mortality during the survey. But that association vanished when the researchers considered demographic and health data. “Our results and those of others suggest that supplement users have higher levels of education and income and a healthier lifestyle overall (for example, better diet, higher levels of physical activity, no smoking or alcohol intake, and healthy weight) than nonusers,” they wrote. Thus, “the apparent association between supplement use and lower mortality may reflect confounding by higher socioeconomic status and healthy lifestyle factors that are known to reduce mortality.”
When the researchers picked apart effects of individual micronutrients, they found that adequate intake of vitamin K and magnesium linked to a lower risk of all-cause mortality. Also, vitamin A, vitamin K, zinc, and copper were associated with a lower risk of death from cardiovascular disease. But these benefits were restricted to intake only from foods—not supplements.
But, before any reader might be tempted to try to bulk-up their diet with foods bursting with those specific vitamins and minerals, the authors add a word of caution. As noted earlier, they suspect that interactions and ratios of nutrients play a role in health outcomes. “Thus, our findings on individual nutrients should be considered exploratory and interpreted with caution,” they conclude.
The study also has several limitations, including relying on people to remember the foods that they eat (and honestly report them). Also, it’s an observational study, only able to pick out correlations, not prove that nutrients cause any observed harms or benefits.
The researchers (as always) call for more research into the wildly popular use of supplements. But conclude from the data so far that, “although adequate nutrient intake from foods could contribute to reduced risk for death, excess intake from supplements might increase mortality.”
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The FDA has sent warning letters to companies marketing dietary supplements.
Jacquelyn Martin/Associated Press
Anne Marie Chaker
April 18, 2019 5:12 p.m. ET
The U.S. Food and Drug Administration said it sent warning letters to 11 companies for marketing dietary supplements that don’t meet its guidelines.
The agency issued warnings to three companies for marketing dietary supplements containing phenibut, which is sometimes sold as a sleep aid or to treat anxiety. It said that phenibut doesn’t meet the statutory definition of a dietary ingredient, which is generally a vitamin, herb or other natural substance used to supplement the diet.
A Wall Street Journal article last week on the $40 billion supplement industry said that phenibut, developed as a drug in the former Soviet Union, was being marketed as a “nootropic,” or brain supplement, in the U.S. A spokeswoman for the FDA said that the agency was already investigating phenibut.
The FDA also issued warnings to eight companies for marketing dietary supplements containing DMHA, a stimulant sometimes found in exercise and weight-loss supplements. The companies have 15 business days to inform the FDA of steps they will take to bring their products into compliance. That could include a decision to recall, reformulate or discontinue sales.
Supplements aren’t tightly regulated by the FDA like prescription drugs. Dietary-supplement manufacturers don’t need approval from the FDA before introducing their products to the market. The FDA has oversight for taking action against any misbranded supplement after it reaches the market.
The FDA said it is launching a new online tool to help warn consumers of ingredients that appear to be unlawfully marketed in supplements. The agency said the Dietary Supplement Ingredient Advisory List will help get cautionary information to the public more quickly before it issues any final determination. It is on the FDA website, and consumers can also sign up to receive updates and changes to the list.
In an effort to better alert the public of unlawful ingredients in dietary supplements, the Food and Drug Administration (FDA) has created the Dietary Supplement Ingredient Advisory List, a new reference tool for consumers and manufacturers.
Available on the FDA website, the list includes ingredients that may not lawfully be included in dietary supplements. Consumers may wish to avoid supplements that include these ingredients as they may not fit the definition of a dietary ingredient or may require pre-market notification that was not submitted; inclusion in this list does not necessarily mean the ingredient poses a safety concern.
“It is important to note that the List is not exhaustive; it will always be a work in progress,” said Frank Yiannas, the FDA’s Deputy Commissioner for Food Policy and Response. “We expect the List will evolve as new ingredients are identified and others are removed.” In addition, the FDA will continue to communicate with the public regarding any safety concerns identified with new dietary supplement ingredients.
In a press statement, Yiannas also noted that the agency recently sent out warning letters to 8 companies that were marketing dietary supplements containing DMHA and 3 companies marketing supplements with phenibut; neither one of these currently meets the FDA’s definition of a lawful dietary ingredient. “We take these violations very seriously and stand ready to take enforcement action without further notice if the companies do not immediately cease distribution of the products,” said Yiannas. In February 2019, the FDA went after 17 companies selling unapproved and/or misbranded products (most sold as dietary supplements) claiming to prevent, treat, or cure Alzheimer disease and other serious disease and health conditions.
Consumers who wish to receive alerts related to updates to the Dietary Supplement Ingredient Advisory List can sign up here.