Nutrition is defined as a biological process in animals and plants involving the intake of food and its subsequent assimilation into the tissues. From the 20th century scientists have identified different nutrients, which constitute the food and have defined nutritional standards and recommendations in order to prevent deficiencies and to promote human health. Nutritional supplements are defined as concentrated sources of nutrients or other substances with a nutritional or physiological effect that supplement the normal diet. At the beginning of the 21st century, increase life expectancy has emerged as new preoccupation for industrial countries and for nutritional science, which one of the challenges is to offer new strategies to improve the quality of human life.1 In this context, nutritional supplements may be used to optimize diet and consequently to improve quality of life. Increased life expectancy is also associated with a need to appear healthy and handsome. Beside the traditional use of topical care, nutritional supplements have emerged as a new strategy to improve skin beauty.
What is a dietary supplement?
As defined by Congress in the Dietary Supplement Health and Education Act, which became law in 1994, a dietary supplement is a product (other than tobacco) that is intended to supplement the diet;
- contains one or more dietary ingredients (including vitamins; minerals; herbs or other botanicals; amino acids; and other substances) or their constituents;
- is intended to be taken by mouth as a pill, capsule, tablet, or liquid; and
- is labeled on the front panel as being a dietary supplement.
Today's dietary supplements include vitamins, minerals, herbals and botanicals, amino acids, enzymes, and many other products.
If you don’t eat a nutritious variety of foods, some supplements might help you get adequate amounts of essential nutrients. However, supplements can’t take the place of the variety of foods that are important to a healthy diet. There are different types of dietary, or nutritional, supplements. Vitamin and mineral supplements are types of dietary supplements containing micronutrients meant to help a body function smoothly and improve mental health. Herbal (or botanical) supplements are dietary supplements that have a medicinal purpose. Herbal supplements generally support a specific area of the body’s health, such as the liver, bones or skin.
Health benefits of vitamin and mineral supplements (micronutrients)
Vitamins and minerals are micronutrients that serve a specific purpose and benefit the body in a unique way. For example, vitamin A supports vision and bone growth, whereas vitamin E strengthens the immune system and helps repair DNA. Vitamin and mineral deficiency can impair the body’s ability to heal and protect itself. Micronutrients can also have an effect on mental health. Studies in New Zealand have shown that using micronutrients in appropriate doses can help treat depression, anxiety, stress, bipolar disorder, ADHD, autism, and PTSD and trauma.
Taking micronutrient supplements won’t make up for an unhealthy diet, though. The basis of healthy eating should always be a diet rich in fresh fruits, vegetables, whole grains, healthy fats, fish and low in processed, fried, sugary, and refined foods. However, some people may benefit from extra nutrients found in a supplement. A general multivitamin and mineral supplement can also be a good safeguard against periodic nutrient shortfalls in your diet.
In general, children and adults might benefit from taking one multivitamin per day. A multivitamin helps provide a consistent source of the necessary vitamins and micronutrients. According to the Harvard School of Public Health, “a daily multivitamin, and maybe an extra vitamin D supplement, is a great way to make sure you’re getting all the nutrients you need to be healthy.”
However, the very first consideration is to eat a healthy diet. Even the best supplement is no substitute for good nutrition. In many Western countries, people tend to consume foods that are high in calories, but lack nutrients that are vital for good health.
Some groups of people, because of distinct nutritional needs, benefit most from taking a vitamin and mineral supplement:
- Women of childbearing age (need extra calcium and iron)
- Pregnant or lactating women
- Children and teenagers with irregular eating habits
- Vegetarians or vegans (may be deficient in key nutrients)
- Dieters or people avoiding certain food groups (may be deficient in key nutrients)
- People with eating disorders or medical conditions (deficiency diseases, absorption problems, lactose intolerance, etc.)
- People who often eat processed and fast food
Dietary supplement safety
Many supplements contain active ingredients that can have strong effects in the body. Always be alert to the possibility of unexpected side effects, especially when taking a new product.
Supplements are most likely to cause side effects or harm when people take them instead of prescribed medicines or when people take many supplements in combination. Some supplements can increase the risk of bleeding or, if a person takes them before or after surgery, they can affect the person’s response to anesthesia. Dietary supplements can also interact with certain prescription drugs in ways that might cause problems.
Keep in mind that some ingredients found in dietary supplements are added to a growing number of foods, including breakfast cereals and beverages. As a result, you may be getting more of these ingredients than you think, and more might not be better. Taking more than you need is always more expensive and can also raise your risk of experiencing side effects. For example, getting too much vitamin A can cause headaches and liver damage, reduce bone strength, and cause birth defects. Excess iron causes nausea and vomiting and may damage the liver and other organs.
Dietary supplements may not be risk-free under certain circumstances. Be sure to consult your health practitioner before purchasing or taking any supplement if you are pregnant, nursing a baby, or have a chronic medical condition such as diabetes, hypertension, or heart disease. Also, while vitamin and mineral supplements are generally considered safe for children, you may wish to check with your doctor before giving these or any other dietary supplements to your child.
Before you decide to take a dietary supplement, ask yourself:
- Do I need this supplement?
- Do I know that this supplement is safe?
- Does this supplement interact with any drug or food I am consuming?
- Do I know that this supplement works?
- Can I afford this supplement?
- Do I know enough about this supplement?
When selecting a nutritional, dietary, or herbal supplement, keep in mind the following:
- Nutritional, dietary, and herbal supplement manufactures are not are required to run studies to determine product safety or efficacy.
- In the U.S., the FDA does not analyze the contents of dietary supplements.
- Dietary supplement manufacturers in the U.S. must meet the FDA’s Good Manufacturing Practices (GMP) for food, but some companies also follow the GMP for drugs on a voluntary basis.
- Specific health claims on dietary supplement labels in the U.S. are not approved by the FDA and must also include a disclaimer that states the nutritional supplement is not intended to “diagnose, treat, cure, or prevent any disease.”
- Daily Value (DV) describes the recommended daily intake of a particular nutritional supplement, if one is established.
In addition, keep in mind the following safety concerns when taking vitamin or mineral supplements:
Don’t substitute dietary supplements for medication
If you’re considering using a dietary supplement in place of drugs, consult your health care provider first. And remember, just because it is “natural” doesn’t mean it’s gentler or more beneficial to your body. Many supplements contain active ingredients that have strong biological effects and their safety is not assured.
Caution: Interactions with other medications
Some dietary supplements may interact with other supplements or prescription and over-the-counter medicines. Taking a combination of supplements or using the products with medications (whether prescription or OTC drugs) can cause dangerous interactions which could be life-threatening.
Some common negative interactions:
- Calcium can interact with heart medicine, certain diuretics, and aluminum and magnesium-containing antacids.
- Magnesium can interact with certain diuretics, some cancer drugs, and magnesium-containing antacids.
- Vitamin K can interact with blood thinners like Coumadin.
- St. John’s Wort is known to adversely affect selective serotonin reuptake inhibitor (SSRI) drugs (i.e., anti-depressant drugs), blood pressure medication, and birth control pills.
- Coenzyme Q-10 can interact with anticoagulants, blood pressure medication, and chemotherapy drugs.
- Ginkgo biloba and vitamin E can increase the risk for internal bleeding when taken with aspirin or anitcoagulants such as warfarin.
- Ginseng can also increase the risk for internal bleeding when taken with anticoagulants or NSAIDs, and may cause side effects when taken with MAOI antidepressants.
- Echinacea can change how the body breaks down certain medications in the liver.
- Saw palmetto can interact with anticoagulants and NSAID pain relievers.
Some dietary supplements can have unwanted effects during surgery
You may be asked to stop taking certain products 2 to 4 weeks ahead of time to avoid potentially dangerous supplement/drug interactions, such as changes in heart rate, blood pressure, and increased bleeding. Talk with your doctor about everything you are taking before the surgery—vitamins, minerals, and herbal supplements, as well as medications.
Dietary supplements and liver damage
Some supplements in the U.S. can contain unsafe ingredients not listed on the label. According to one study, about 23,000 visits to the Emergency Room each year are attributed to dietary supplements, and the most common consequence is liver damage. Weight-loss and muscle building supplements carry the highest risk.
More isn’t always better
Even if your body can benefit from a certain supplement, in excessive doses it may still cause health problems. For example, drinking green tea may provide fat-burning and antioxidant benefits, but taking high-concentration green tea supplements can be toxic to the liver.
- Taking too much selenium and vitamin E may increase the risk for prostate cancer.
- Beta-carotene beyond the amount included in a daily multi-vitamin may increase the risk of lung cancer in smokers.
Reasons of taking supplements
Many people still question the importance of taking supplements at all. Here are ten reasons to consider supplementing your diet with high-quality nutrients:
- Current commercial agriculture techniques leave soil deficient in important minerals, causing the food grown in this soil to share the same mineral deficiencies.
- Many foods are shipped long distances and are stored for long periods of time, both of which cause the depletion of vitamins in these foods, including the important B-complex and C vitamins.
- Food processing, cooking, and preserving leads to nutrient depletion in our food supply that makes it difficult to obtain adequate nutrition from foods alone.
- Many fruits and vegetables are genetically bred to improve visual appeal and crop yields, not nutritional value, which frequently results in lesser nutritional values than our ancestors’ food supply.
- Erratic eating habits, insufficient chewing of food, eating on the run, and stress contribute to poor digestion, making it difficult for our bodies to extract all the nutrients it needs from food.
- Pharmaceutical drug use has escalated over time. Most medications deplete essential nutrients, making people more vulnerable to deficiencies.
- Specific times in life and health conditions may result in higher needs of certain nutrients. For example, folic acid needs tend to be higher during pregnancy, while menopausal women may be vulnerable to calcium deficiencies.
- Increasing levels of environmental pollution in our air, water and food may cause our bodies to use more nutrients than normal to detoxify and eliminate harmful substances. This is especially true of the antioxidant vitamins, some of which include: the “ACE Vitamins:” Vitamins A, C, and E.
- We all have genetic weaknesses, including higher needs of some nutrients, higher rates of depletion for certain nutrients, and an increased likelihood of genetic expression of some illnesses if vitamin or mineral deficiencies are present.
- Many nutrients have been proven to prevent or aid in the treatment of health conditions like high cholesterol, arthritis, birth defects, and cancer.
Of course, you should always consult a qualified health professional first to avoid any drug-nutrient interactions. And avoid supplements with sweeteners, colors, artificial flavors, preservatives, or fillers. Children should always take supplement formulas designed for their needs.