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 Healths 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 bodys 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 NIHs Office of Dietary Supplements. The numbers on the whole tend to work out. Youll 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 arent 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, its 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.

Nutrition cant be reduced to a list of nutrients and numbers, Thomas said. Thats because the science isnt complete, he explained, and because humans dont 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 cant 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 dont 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 persons 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.

But I was aware that I was experimenting, that I was going beyond the bounds of any professional, generally accepted recommendation for its use, he said. And in my case, it helped. There have been other cases where it hasnt been helpful.

Each supplement has its own characteristic benefits and potential risks, Thomas said. Experts said if the benefits dont show up after youve given the supplement a good try, then discontinue it.

Because it can be difficult to track down the cause or causes of your bodys negative reactions to something, Thomas recommends adding only one supplement at a time and watching how you react to it.

He also urges consumers to examine the reputation and reliability of a supplement maker, to ensure theyre getting the actual supplement and no dangerous byproducts or even contaminants.

The nutritional supplements industry and the nutrient recommendations we have today began in the early 1940s in the shadow of World War II, Thomas said.

Recommended dietary allowances of vitamins and minerals were established through the National Academy of Sciences. Around the same time, sales began of multivitamin/mineral supplements, according to the Office of Dietary Supplements.

Many potential recruits were in poor nutritional status, Thomas said. That led to a project to better understand nutritional needs and set standards to help the military and civilian populations get adequate amounts of essential nutrients, including protein and carbohydrates.

Over the years, for subsequent iterations, the number of nutrients has expanded as our understanding of their role and potential numerical requirements were better understood, Thomas said.

The governments last update of recommended dietary allowances took place in 1989.

I was working at the National Academy of Sciences at that point, with the Food and Nutrition Board, Thomas said.

The board established what it calls Dietary Reference Intakes, intended to define consumption of vitamins and minerals by healthy people. These include maximum levels of safe consumption of each nutrient.

The intake thresholds dont apply to people suffering from various diseases, because they likely have different nutritional needs.

For those worried theyre falling a little short of the allowances, Thomas said isnt necessarily a problem. The recommendations are conservative, estimated to cover 97.5 percent of the U.S. population, he said.

So falling just short of the recommendation for a vitamin or mineral doesnt necessarily mean you personally are deficient.

Supplements not on the official list can be sold as food products, not drugs, under the Dietary Supplement Health and Education Act of 1994. These items cant legally be sold to treat diseases, but can be marketed as supporting various aspects of health. The products include biological molecules such as coenzyme Q10, creatine, glucosamine, omega-3 fatty acids, gingko, kava, milk thistle and many more.

For a comprehensive list of supplements, go to j.mp/supplementdiet.

Of all supplements, vitamin D, is perhaps the most controversial. Its necessary for health, but the medical community is sharply divided on how much is needed for the best health.

In theory, most people can get all the vitamin D they need by exposing most of the top half of their body to the sun for 10 to 15 minutes a day. But those who live in higher latitudes or dont expose themselves to the sun for reasons such as fear of skin cancer cant rely on that source. The only other sources are foods, mostly from animals, and supplements.

Top vitamin D experts like Cedric Garland, a UC San Diego epidemiologist, said vitamin D deficiency is common in society. They said the amounts recommended by the federal government are enough to prevent obvious problems such as rickets, but that studies of disease patterns show a striking correlation with lack of vitamin D and higher latitudes.

Rates of the diseases in question drop as you get closer to the equator. The geographic pattern produces a map that researchers call the Vitamin D smile.

That view is highly debated. Some researchers have said proponents of the vitamin D theory have mixed up cause and effect. In other words, lower vitamin D levels could be the result of certain diseases, not their cause.

On Monday, vitamin D supplementation advocates got an endorsement from a review article published in The Journal of the American Osteopathic Association. That article said nearly 1 billion people worldwide may have insufficient or deficient levels of vitamin D due to disease or lack of exposure to the sun.

Garland said the literature on relationships between diseases and a lack of vitamin D is extensive, along with the existence of widespread deficiencies.

Examples are easy to find. From 2016 to the present studies have reported:

* More than half of college football athletes in the NFL Combine have inadequate levels of vitamin D.

* Increasing nursing mothers' vitamin D levels may benefit babies

* In a study performed in mice, giving vitamin D to pregnant mice prevented signs of autism in their offspring.

To get the full benefits of vitamin D, blood measurements should show at least 32 nanograms per milliliter, Garland said.

Theres a threshold for the non-skeletal effects, Garland said. The older standard of 20 nanograms per milliliter would prevent rickets and some perhaps some heart disease, he said.

But we have the potential to reduce cancer, and maybe multiple sclerosis and type 1 diabetes, he said.

Distinguishing between cause and effect has been demonstrated in randomized controlled trials of Vitamin D supplementation, Garland said. For example, a 2007 randomized controlled study published in the American Journal of Clinical Nutrition found increasing calcium and vitamin D levels substantially reduced the risk of cancer in more than 1,100 postmenopausal women.

Quality counts

Focusing on food is good, but where it comes from and how it is grown makes a difference, said Kelli Gray-Meisner, a registered dietitian at UC San Diego.

For example, chickens exposed to sun are going to have more vitamin D, Gray-Meisner said.

We mainly get vitamin D from animal sources, she said. Mushrooms are the main exception, and its in a less bioavailable form, vitamin D2. The preferred form is vitamin D3, which is already activated.

Even with those precautions, Gray-Meisner said most people probably should take some supplement, to ensure theyre adequately protected. this includes fish oil with omega-3 fatty acids. Most people have a diet that gives them too much omega-6 fatty acids, which can cause harmful inflammation, she said.

Because of the line of work that Im in, I dont make blanket statements, because I look at people one at at time, she said. But in general, most people could benefit from a multivitamin based on their age and gender several days a week, because we need different things at different times in our lives.

The other consideration is the state of the food, she said.

Even if somebody had a perfect diet in my eyes, our soil and the quality of our plants, which our animals eat, has been degraded over the years, she said. The amount of nutrition that was in an apple 50 years ago is very different from whats in an apple today.

The best plant foods come from areas where the nutritional value of the soil has been conserved through good management, she said.

In general, organically raised produce doesnt strip the soil of nutrients because of the techniques used, Gray-Meisner said.

And for animal products, their nutritional value is based on the quality of the plants they eat. That means grass-fed beef will have a much better nutritional profile than beef raised on artificial feeds.

It has a lot more vitamin A and vitamin D, the ratio of omega-6 to omega-3 is 1 to 1. It goes back to diet; the diet of the animal, and the diet of the plant that theyre eating, which is what they get from the soil.

To get the most nutritional value, Gray-Meisner suggests stopping by your local farmers market.

As soon as food is picked or cut, it starts to lose nutrients. The sooner you can get the produce from the ground and into your mouth, the better off youre going to be.

bradley.fikes@sduniontribune.com

(619) 293-1020

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Do we really need all these vitamins, minerals and other ... - The San Diego Union-Tribune