Do we really need all these vitamins, minerals and other … – The San Diego Union-Tribune
The problem with nutritional science is it isn’t really a science. It’s a mixture of science with tradition, fads and prejudices — often it’s hard to see which is which.
And human beings are notoriously hard to study. We vary by gender, race, genetics, cultural backgrounds and the physical environments in which we live, work and play.
So what should we eat, and avoid, for proper nutrition? Should we take vitamins and other dietary supplements — and if yes, what kinds?
Judging by statistics, Americans have already given their answers. About 71 percent of us take dietary supplements, according to the Council for Responsible Nutrition, a trade association for the supplements industry.
Multivitamins are the most common form, with 75 percent of supplement users taking them. Vitamin D comes in second at 37 percent, followed closely by vitamin C at 34 percent and calcium at 29 percent.
Sales of all vitamin- and mineral-containing supplements in the U.S. totaled $14.3 billion in 2014, according to the National Institutes of Health’s Office of Dietary Supplements. Sales of all dietary supplements reached $36.7 billion in that same year, the most recent period available for finalized data.
But resoundingly, nutritional experts said you should start by focusing on food. Know which foods provide which of your body’s nutritional needs, and then build your balanced meals with those items. Even the nutritional supplements industry says that.
The Council for Responsible Nutrition says supplements should be secondary to adopting an eating pattern that includes foods with good nutritional profiles.
“We always look at diet first,” said council spokesman Douglas “Duffy” MacKay. “Supplements are there to fill gaps. … Diet is the target, but we have to live in the real world.”
“To many nutritionists, the issue is not really nutrients and their actual numbers, but your diet and the foods you take from a variety of different groups,“ said Paul Thomas, a scientific consultant for the NIH’s Office of Dietary Supplements. “The numbers on the whole tend to work out. You’ll be in pretty good stead if you follow the Dietary Guidelines for Americans.”
Every five years, the federal Office of Disease Prevention and Health Promotion issues its Dietary Guidelines for Americans. The most recent set dates back to 2015.
The guidelines advocate what are called “healthy eating patterns,” sounding the familiar refrain of eating more vegetables, fruits, whole grains and dairy, such as fat-free or low-fat milk, and reducing sodium intake.
The 2015 report notably differs from its 2010 predecessor in dropping the limit on consuming cholesterol. Yet cholesterol, along with fat and sodium, is still treated with suspicion. The guidelines on those substances aren’t firmly supported by accumulating scientific evidence.
*Fat, demonized for decades as causing heart disease and obesity, is now known to be much more benign. Evidence indicates heart disease is an inflammatory condition with little connection to fat. And some fats are actually good for your heart.
Dr. Eric Topol, a Scripps Health geneticist-cardiologist in La Jolla, has called the emphasis on restricting fat an example of “eminence-based medicine,” in which the eminence of the proponent outweighs the evidence.
*Dietary cholesterol, likewise long condemned as a heart-killer, has little to do with blood cholesterol levels. The body makes cholesterol as needed. Efforts to find a link between cholesterol consumption and heart disease have yielded inconclusive results, meaning the federal dietary guidelines lack clear scientific support.
*Sodium intake has little to do with blood-pressure levels — a finding repeatedly documented in studies, including a new one that followed 2,600 people for more than 16 years. Sodium mainly enters our food through salt. Roughly 25 percent of Americans are salt-sensitive and need to watch their intake. For the rest, it’s not a critical issue.
The current dietary guidelines also point out vitamin and mineral deficiencies in the diet of many Americans.
“These include potassium, dietary fiber, choline, magnesium, calcium and vitamins A, D, E and C,” they said. “Iron also is under-consumed by adolescent girls and women ages 19 to 50 years.”
Not a numbers game
Nutrition can’t be reduced to a list of nutrients and numbers, Thomas said. That’s because the science isn’t complete, he explained, and because humans don’t consume nutrients in isolation.
“Food is really complicated,” Thomas said. “It not only contains nutrients for which we have recommended allowances, it contains a whole variety of other things that seem to be important to health that we can’t quite quantify yet. By not eating those foods and thinking you can make up the nutrient deficit by taking individual (supplements) or combinations of them, you are depriving yourself of these other things that can potentially affect your health.”
Still, for people who don’t fully follow the federal dietary guidelines, Thomas said the next-best thing is to add well-targeted supplements in consultation with a doctor or dietitian.
A supplement, as the name implies, is any substance taken to augment a person’s diet. These can be necessary vitamins or minerals, or optional substances thought to support or improve health.
Along with the standard vitamin and mineral supplements, companies offer what are called “specialty supplements,” including coenzyme Q10 to supply energy and glucosamine and chondroitin for joint function, he said.
Curcumin is another popular supplement in the specialty category, MacKay said. This component of the curry spice turmeric has anti-inflammatory properties. Research indicates it may help prevent Alzheimer’s disease and cardiovascular disease.
Thomas considered supplements after developing osteoarthritis, a common aging-related condition, a number of years ago. “I still wanted to run and play singles tennis and all,” he recalled.
After reviewing the scientific evidence and talking with his physician, Thomas took glucosamine and chondroitin. The studies were conflicting as to their effectiveness, but the supplements also had a good safety profile. So Thomas decided it was worth a try.
“In my case it helped. It helped wonderfully,” Thomas said. He began sensing effectiveness within a few weeks, without any side effects, and the benefits lasted about five years.