Vitamins and supplements:
Understanding when and how to use them
Should you be taking vitamins and supplements? If so, which ones? Are there any real benefits? What about risks? Most of us have asked these questions in one form or other. So what does the science say.
At present about half of American adults take a multivitamin. But taking a multivitamin should not keep you from eating a varied and nutritious diet. Studies on taking vitamins to prevent disease have been disappointing. They have not shown that a multivitamin can replace a healthy diet; one high in fruits and vegetables.
Vitamins and supplements: The Study
The Harvard-led Physicians Health Study II (PHS II), an 11 year study of 15,000 doctors taking vitamins and supplements published in 2012, found:
- No effect on the risk of heart attacks, strokes and death from cardiovascular disease.
- And an 8% decrease in the risk of being diagnosed with cancer.
What does it mean?
It is difficult to relate these results to the average American. Compared to most people, the doctors in the study ate better diets, were more active and had fewer unhealthy habits.
- Less than 4% were smokers
- 60% exercised at least once a week.
By comparison, the average American is overweight, does not exercise as much and takes in too much fat and sodium. Would a multivitamin help?
Taking Vitamins and supplements
When it comes to vitamins and supplements more is NOT better. These nutrients can be harmful when taken in amounts above what is considered good for you.
Deciding on the right dose of vitamins and supplements is tricky. Each has a range that starts with the lowest daily dose necessary to meet the needs of most healthy people. This is called the Recommended Dietary Allowance (RDA). The highest dose is the upper intake level (UL) for each particular nutrient that a healthy person can tolerate. The correct dose must be determined for each person and must be based on each individual’s needs, so talk to your doctor before taking new vitamin and mineral supplements.
Vitamins and supplements vs food
Food contains a variety of healthful ingredients and is a better source of nutrients than vitamins and supplements. Stop and ask why you think you need them and what you expect to gain, if planning to take vitamins and supplements. Remember:
- Vitamins and supplements are not going to replace nutrients missing from your diet.
- The money you are spending on vitamins and supplements, is best spent at the farmer’s market or grocery store on healthy foods.
Vitamins and supplements: who needs them?
If you are convinced you need vitamins and supplements here are a few things to know.
The Dietary Guidelines for Americans make the following recommendations:
- People over age 50 should take vitamin B12 in its crystalline form, as in fortified foods (like some fortified breakfast cereals) or as a supplement .
- Older adults often have a reduced ability to absorb vitamin B12 from food.
- Crystalline vitamin B12, the type used in supplements and fortified foods, is much more easily absorbed.
- Pregnant women and those in their child bearing years should eat foods that are a source of heme-iron (such as meats).
- They should eat iron-rich plant foods (like cooked dry beans or spinach) or iron-fortified foods (like fortified cereals).
- Pregnant women and those in their child bearing years should eat foods that area a rich source of vitamin C.
- They should take in adequate synthetic folic acid daily (from fortified foods or supplements) in addition to food forms of folate from a varied diet.
- Older adults, people with dark skin, and people who get insufficient exposure to sunlight should consume extra vitamin D from vitamin D-fortified foods and/or supplements.
Vitamins and supplements: The deciding factors
It can not be overstated, vitamins and supplements are not a replacement for a healthful diet. Foods also contain hundreds of additional natural substances that help protect your health.
The Food and Drug Administration (FDA) recommends asking yourself and discussing with your doctor the following questions, when considering whether you should take vitamins and supplements:
- Do you eat fewer than 2 meals per day?
- Is your diet restricted? Do you not eat meat, or milk or milk products, or eat fewer than 5 servings of fruits and vegetables per day?
- Do you eat alone most of the time?
- Without trying, have you lost or gained more than 10 pounds in the last 6 months?
- Do you take 3 or more prescription or over-the-counter medicines a day?
- Do you have 3 or more drinks of alcohol a day?
You and your doctor should work together to determine if a vitamin or mineral supplement is right for you. If you are already taking dietary supplements, you should inform your doctor. Studies show that many people don’t inform their doctors about dietary supplements they take or are considering taking.
- Your doctor is a good source of valid scientific information about vitamins and supplements.
- Other good sources are pharmacists and registered dietitians.
- The National Institute of Health (NIH) Office of Dietary Supplements, has a series of Vitamin and Mineral Fact Sheets that provide scientific summaries for a number of vitamins and minerals. They can be a good discussion starter for you and your doctor about your need for vitamin and mineral supplements.
- MedlinePlus is another good source of information.
- The Food and Drug Administration (FDA) has many of articles and consumer advisories to inform consumers about dietary supplements. They cover things such as warnings, safety, labeling and evaluation information and describe the FDA’s role in regulating dietary supplements.
- If interested in looking directly at scientific studies, the PubMed Dietary Supplement Subset is a good database to search.
Vitamins and supplements complications
If you believe side effects only happen with prescription medicines, think again. Some vitamins and supplements can cause side effects when taken with other medications or when certain health problems exist. Even if you don’t take medication or have a chronic health problem, the wrong dietary supplement or the wrong amount, can cause problems. So check with your doctor before taking a dietary supplement.
Dealing with side effects
If you suspect you are having a side-effect from a dietary supplement,
- Stop taking it immediately.
- Contact your doctor or health care professional.
- The MedWatch Reporting Program also gives you information about how to report a problem to the Food and Drug Administration.
In summary, check with your doctor or registered dietitian about which, if any, vitamins or supplements might be right for you. Remember that while there are times when it may be appropriate to take a vitamin or mineral supplement, the best source is still a healthful diet.
Demystifying nutrition: the value of food, vitamins and supplements Longwood Seminars, March 5, 2013