Vitamin and Mineral Supplements – What Doctors and Users Should Know

In the United States alone, dietary supplements comprise more than 90 thousand products in a market worth approximately 30 billion dollars. Interest in alternative products grows worldwide each year. A recent United States study found that 52% of adults used at least 1 dietary supplement, and 10% used at least 4 simultaneously. Among these many supplements, vitamins and minerals are the most preferred, used at rates of 48% - 39% to stay healthy and prevent disease.

Despite widespread use for these purposes, most scientific clinical trials have not proven these supplements effective in preventing chronic diseases. More strikingly, while only people with nutritional deficiencies or specific medical conditions may benefit, the problem in developed and developing populations is not undernutrition but overnutrition (overweight and obesity). Vitamins and minerals already consumed excessively through the existing diet are therefore supplemented further.

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Many studies associate intake above recommended dietary amounts of beta-carotene, folic acid, vitamin E and selenium with increased mortality, cancer and hemorrhagic stroke rates.

One of the world’s leading scientific journals, JAMA, therefore published a comprehensive guide in February 2018 to help doctors inform patients accurately about these supplements. We wanted to share this article with you.

Inappropriate supplement use by healthy people should be prevented.

These supplements, whose benefits are unproven and which carry risks, do not replace a healthy, balanced diet.

Doctors should emphasize that obtaining vitamins and minerals from food is far more advantageous than supplements. Micronutrients consumed with food are better absorbed and cause fewer side effects. A healthy diet provides a range of essential substances in biologically optimal proportions rather than isolated ingredients at high concentrations.

Routine micronutrient supplements are not recommended for the general population; targeted supplements should be reserved for people at high health risk or whose nutritional needs are unmet.

Key Points About Vitamin and Mineral Supplements – Who Needs Them?

• Pregnancy: folic acid, prenatal vitamins.
• Infants and children: vitamin D for breastfed infants until weaning, and iron from months 4-6.
• Older age: some may benefit from extra vitamin B12, vitamin D and/or calcium (blood levels should be checked).

Supplement guidance for high-risk subgroups

Medical conditions affecting nutrient absorption or metabolism:

• Bariatric (obesity) surgery: fat-soluble vitamins, B vitamins, iron, calcium, zinc, copper, multivitamins / multiminerals.
• Pernicious anemia: Vitamin B12
• Crohn’s disease, other inflammatory bowel disease, celiac disease: iron, B vitamins, vitamin D, zinc, magnesium.
• Osteoporosis or other bone health problems: vitamin D, calcium, magnesium*
• Age-related macular degeneration: an eye disorder. A special formulation of antioxidant vitamins, zinc and copper.

Needs arising from long-term use of certain medications:

• Proton pump inhibitors*: stomach acid-reducing drugs. Vitamin B12, calcium, magnesium
• Metformin*: diabetes medication. Vitamin B12
• Restricted or suboptimal diets: for example, veganism or vegetarianism. Multivitamins / multiminerals, vitamin B12, calcium, vitamin D, magnesium

*: evidence is unclear

Pregnancy

Evidence recommends that women who may become pregnant or are in their first trimester consume enough folic acid to prevent nervous system problems (neural tube defects). Folic acid is a micronutrient vitamin, naturally present in dietary form (folate) in greater amounts than synthetic forms. Prenatal multivitamin/multimineral supplements provide vitamin D and many other micronutrients alongside folic acid. Pregnant women should also be advised to eat an iron-rich diet. For those with low hemoglobin and ferritin, iron-deficiency anemia prevention and treatment may require iron supplements, although the benefit-risk balance of anemia screening and routine iron supplementation during pregnancy is not well defined.

Calcium supplements may reduce gestational hypertension and preeclampsia risk, but larger confirmatory studies are needed. More research is also required on high-dose vitamin D during pregnancy. In summary, the strongest evidence for pregnancy supplements concerns folic acid; others remain controversial.

Infants and children

American Academy of Pediatrics recommendations:

• For exclusively or partially breastfed infants , vitamin D supplementation (400 IU daily),
• From month 4, iron supplementation (1mg per kilogram daily),
• All children should be screened at 1 year for iron deficiency and anemia.

Healthy, well-nourished children do not need multivitamin/multimineral supplements, and excessive micronutrient intake should be prevented.

In recent years, omega-3 fatty acid supplements have been considered potentially useful in children for reducing autism and attention-deficit/hyperactivity disorder risk, but large studies have not provided evidence sufficient to recommend them.

Middle-aged and older adults

In people aged 50 and older, vitamin B12 intestinal absorption problems are more common. Supplementation after age 50 is therefore recommended according to blood B12 levels.

Adequate calcium and vitamin D intake is known to matter for bone health. Low vitamin D levels, even in those believing they receive enough sunlight, are portrayed as though vitamin D causes many disorders. The most comprehensive study in this field, published in December 2017, showed that vitamin D and calcium supplements did not reduce fractures in older people. Similarly, in April 2017, JAMA published another study showing that monthly high-dose vitamin D supplements do not protect against cardiovascular disease . Multivitamin/multimineral supplements are therefore not recommended for healthy adults. Based on current evidence, vitamin D supplementation should be considered if blood tests demonstrate deficiency.

Other key points

When prescribing medication, doctors should counsel patients about potential interactions and micronutrient use, including botanical and other supplements. Vitamin K supplements may reduce the effectiveness of the blood thinner warfarin, while biotin (vitamin B7) may affect cardiac troponin and other laboratory test accuracy. Reliable websites now check drug-food-nutrient or herbal supplement interactions; Google searches for "drug interaction" can find these free applications.

Safety and standardization of nutritional, vitamin, mineral or herbal supplements is another concern. These products are not regulated as strictly as drugs. In recent years, analysis finding no omega-3 fat in omega capsules sold by one of the largest companies made headlines. Doctors should therefore consider prescription products. These contain the labeled doses and active ingredients, without microbes or heavy metals.

In conclusion, doctors have an opportunity to prevent inappropriate micronutrient supplement use and encourage appropriate use for a limited number of health problems. Such efforts may improve public health.

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