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Nutritional Supplements: A Primer

Dietary supplements used widely in the US

By Tina Willis, MA, RD, CD | 06.14.2010
Originally Published June 2010
Dietary supplements

Millions of Americans use dietary supplements in pursuit of better health. The dietary supplement industry in the US alone is a $23.7 billion enterprise.1 It is estimated that 64% of American adults use dietary supplements, the top three of which are multivitamins, vitamin C and calcium. Twenty-one percent take some type of botanical supplement, the most popular being green tea, garlic and echinacea. What effect do dietary supplements have on your health, particularly for people with hemophilia, von Willebrand disease and other bleeding disorders?

[Steps for Living: Nutrition and Weight Management]

In the US, the Dietary Supplement Health and Education Act of 1994 defines a dietary supplement as containing one or more vitamins, minerals, herbs or other botanicals, amino acids, concentrates, metabolites, constituents, extracts or any combination of these. In addition, it must be intended to be taken in the form of a pill, capsule, powder or liquid. Further, it must not be represented for use as a food or the sole item of a meal or diet. It must also be labeled as a dietary supplement.

The US Food and Drug Administration (FDA) is responsible for the regulation of all dietary supplements, which are treated as foods, not drugs; therefore, they do not need to be preapproved by the FDA prior to entering the market. In June 2007, the FDA ruled that by June 2010, the production of dietary supplements must comply with “current good manufacturing practices,” which require products industry-wide to be processed in a consistent manner and meet quality standards. Supplements must also be free of contamination and have accurate labeling. The supplement industry is now required to report to the FDA all dietary supplement-related adverse effects.

The FDA’s authority is restricted, however. Supplement manufacturers can launch products without testing them as long as they send the FDA a copy of the language on the label and refrain from declaring that the product treats, prevents or cures a specific disease or ailment.2 Always consult with your physician/hematologist before beginning any dietary supplement therapy.

Herbal Supplements

Herbal remedies have likely been used for centuries. The first documented use of herbs was in 2800 BC in China. They have remained popular throughout the world since then, being used as sleep aids, digestive aids, treatment for skin disorders and as general healing agents. But with the advent of pharmaceuticals in the 1800s, they began to decline in popularity. During World War I, when prescription drugs were in short supply, their use rebounded.2

Today, herbal supplements have become increasingly popular. Herbal treatments, along with the methods of delivering them, have improved, largely due to continued research and clinical trials.

Many people use herbal remedies to prevent specific ailments or to complement more traditional medical treatments. Others who are wary of the potential side effects of some pharmaceuticals are instead seeking alternative ways to improve or maintain their health in a more natural manner. Herbs used today are generally cultivated for specific purposes. Some people are also beginning to cultivate and grow their own herb gardens.

Herbs are sold in many forms: fresh or dried products, liquid or solid extracts, and tablets, capsules or powders. Herbal products are often promoted as “natural,” which causes people to believe they are safe. While they can be safe and beneficial to take, herbs can act in a similar manner to drugs. They can cause physiological damage if not used correctly, if taken in amounts not recommended or with other herbs or drugs not recommended, or if taken by individuals with certain medical conditions. The following are just a few examples of the two sides of certain herbs.

Garlic is used to treat or prevent heart disease, high cholesterol and high blood pressure. It is generally considered safe, but side effects can include upset stomach, headaches and fatigue. It also may cause increased bleeding and interact adversely with insulin, anticoagulants, immunosuppressive agents and protease inhibitors, such as those used for HIV therapy.

Ginger is best known for its anti-nausea properties. It is generally considered safe but may interact with the prescription blood thinners heparin, Ticlid and Coumadin, drugs that are contraindicated in people with bleeding disorders. Ginger may also increase the risk of bleeding.

Milk thistle has a long history of use for liver diseases, such as cirrhosis and hepatitis, and gallbladder disorders. However, people with bleeding disorders who have a liver condition should contact their healthcare provider before using milk thistle. Side effects may include indigestion, headache and itching. People with allergies to daisies, artichokes or kiwi may also experience allergies to milk thistle. Milk thistle may lower blood sugar levels and may reduce the effectiveness of oral contraceptives.

Ephedra was previously a popular weight-loss supplement and was also used to enhance sports performance. It has been linked with flushing and sweating, irregular or rapid heart rhythms, heart damage, strokes, seizures, psychosis and death. Dietary supplements containing any amount of ephedra have been banned in the US since 2006.3

Ginkgo biloba has been traditionally used to improve mental function, to slow macular degeneration and to improve blood circulation. Ginkgo may increase the effect of antiplatelet or anticlotting drugs, which may result in uncontrolled bleeding or hemorrhage. It may also decrease the effectiveness of immunosuppressant drugs and adversely affect the use of insulin and oral diabetes drugs.

Vitamins

A vitamin is an organic compound an organism requires as a nutrient in tiny amounts. Approximately 3,500 years ago, ancient Egyptians discovered that giving liver to certain individuals could help treat night blindness. Today, we know that it was the vitamin A that improved vision.

Despite this, much of the knowledge about vitamins was not used for many centuries. In 1749, Scottish surgeon James Lind discovered the nutrient we know today as vitamin C. He found that citrus fruits helped to prevent scurvy, an ultimately fatal disease that causes loose teeth, open wounds, lack of energy and depression. This discovery was largely ignored until 1911, when a Polish chemist, Casimir Funk, discovered vitamins, or vital amines.4

All naturally occurring vitamins are found only in plants and animals. With only a few exceptions, the human body cannot manufacture its own vitamins; they must be obtained from food or supplements.

Vitamins have many functions. They help regulate metabolism, convert fat and carbohydrate into energy and aid in the formation of healthy bones and tissues. They do not prevent or cure such diseases as cancer or aging-related disorders. However, they can help fortify the immune system and provide some protection against such illnesses.

While each vitamin plays a specific role in the human body it does not typically act alone. Often, two or more vitamins and minerals will interact to successfully create the desired result.

Vitamins are classified into one of two categories: water-soluble and fat-soluble. Water-soluble vitamins are the B vitamins (thiamine, riboflavin, folate, cobalamin, biotin, pantothenic acid and pyridoxine) and vitamin C. Because they are not stored in the body, foods that supply these vitamins need to be eaten daily.

Fat-soluble vitamins A, D, E and K are digested and absorbed into the human body with the help of fats in various foods. Fat-soluble vitamins can be stored in the body to use when the body needs them.

The following are a few examples of vitamins and their importance in our diets:

Folate plays an essential role in making new body cells. It also works with vitamin B12 to form hemoglobin in red blood cells and may protect against heart disease. A folate deficiency may result in a type of anemia. Pregnant women who do not get adequate folate early in pregnancy have a greater risk of having a baby with neural tube defects, birth defects of the brain and spinal cord such as spina bifida. Too much folate may mask a B12 deficiency. Folate may also interfere with certain medications.

Vitamin K is important in the body’s normal production of some clotting factors. It is produced in the gut by certain bacteria. Prolonged use of antibiotics can destroy some of the intestinal bacteria that produce vitamin K. If a deficiency does occur, blood will not clot properly. People with bleeding disorders could become deficient in Vitamin K if they become malnourished; in those cases, their bleeding pattern could become more pronounced.

Vitamin C helps produce collagen, a connective tissue that holds muscles, bones and other tissues together. It also helps keep capillary walls and blood vessels firm, protecting the body from bruising. It helps the body absorb iron and folate from plant sources of food, keeps gums healthy, helps in the healing of cuts and wounds, protects individuals from infection and acts as an antioxidant. A deficiency may lead to scurvy. An excess amount is typically excreted in urine because it is a water-soluble vitamin. This can, however, mask the results of urine tests for diabetes. Mega-doses can cause kidney stones or diarrhea.

Vitamin A promotes normal vision and the growth and health of the body’s cells and tissues. It works as an antioxidant to possibly reduce the risk of certain cancers and some diseases of aging. A deficiency in vitamin A may lead to eye problems; dry, scaly skin; reproductive problems; and poor growth. Excess amounts are stored in the body and can be harmful over time. They can result in headaches, liver damage, bone and joint pain, abnormal bone growth, nerve damage and birth defects.

Vitamin D promotes the absorption of calcium and phosphorus and regulates the amount of calcium in the blood. It also helps deposit these minerals in bones and teeth, making them stronger and healthier. A deficiency may increase the amount of bone loss and the risk of osteomalacia or osteoporosis. Excess amounts stored in the body can be toxic and could lead to kidney stones or weak bones.

Vitamin E works as an antioxidant. It may help prevent the oxidation of LDL cholesterol (low-density lipoprotein, or “bad” cholesterol) and, in turn, lower the risk for heart disease and strokes. Deficiencies are rare, although people with poor fat absorption, such as preterm infants and people with cystic fibrosis, may be at risk since vitamin E is a fat-soluble vitamin. An excess amount may impair the action of vitamin K and increase the effect of anticoagulant medication. In people with bleeding disorders, it may worsen the bleeding symptoms.

Minerals

Food minerals are found in small amounts and help our body’s organs, systems and bones perform vital functions. For example, calcium helps grow and maintain healthy bones, while zinc helps our immune system function optimally.

There are two classifications of minerals: macro minerals and trace minerals. An individual needs more of macro minerals, such as calcium, potassium, sodium and phosphorus, but smaller amounts of trace minerals, such as zinc, iron, copper and fluoride. As with vitamins and herbs, people can get sick by ingesting too much of any one mineral.

The following are examples of some minerals and their importance in our diet:

Calcium is the most abundant mineral in the body. Nearly all of it is stored in bones and teeth, making them strong. It also plays a role in blood clotting, muscle contraction and hormone secretion. A deficiency may result in brittle bones, while an excess may lead to hypercalcemia, which can cause constipation, bone pain, kidney stones, depression or confusion. The body needs vitamin D to use calcium.

Magnesium plays a role in more than 300 body enzymes. It also helps muscles relax and contract. A deficiency is rare. Excess magnesium is usually not a problem unless a person has kidney disease and is unable to excrete excess amounts.

Potassium helps regulate body fluids and mineral balance in and out of body cells, helps maintain a normal blood pressure, helps transmit nerve impulses and aids in muscle contraction. Deficiency is rare unless there is prolonged vomiting, diarrhea or laxative use, which could result in muscle cramps, weakness, loss of appetite, nausea and fatigue. Excess amounts are typically excreted. However, people with impaired kidney function may be unable to rid the body of excess amounts, and cardiac problems may subsequently ensue.

Sodium helps regulate the movement of body fluids in and out of cells, helps muscles relax, aids in the transmission of nerve signals and helps to regulate blood pressure. A deficiency is rare unless there has been prolonged vomiting or diarrhea. Excess sodium is typically excreted in the urine. Someone with a kidney disorder, however, may experience fluid retention and swelling. A diet high in sodium may also contribute to elevated blood pressure.

Iron serves as an essential part of hemoglobin, which carries oxygen throughout the body. It also helps support a healthy immune system. Iron deficiency can lead to anemia, fatigue and infections. Iron deficiency is common among women with regular menstrual periods, including those with bleeding disorders, and during and after pregnancy. In the US, iron deficiency is the most common nutrient deficiency. Excess consumption can lead to a dangerous buildup of iron, called hemochromatosis, for those genetically predisposed to it.

Fish Oil Supplements

Fish oil is an omega-3 fatty acid derived from the fatty tissues of fish. It contains two types of omega-3 fatty acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which help reduce inflammation within the body. There is evidence that taking the recommended amount of DHA and EPA in the form of fish or fish oil supplements may provide cardiovascular protective benefits, such as lower triglycerides and blood pressure. It may also slow the buildup of atherosclerotic plaque.

However, omega-3 fatty acids may increase the risk of bleeding, and large intakes of fish oil supplements may increase the risk of hemorrhagic strokes. Higher intake has also been associated with nosebleeds and blood in the urine. Additionally, fish oils are thought to interfere with platelet aggregation and prolong bleeding. Therefore, the risk appears to outweigh the benefit in people with bleeding disorders.

Other side effects of fish oil supplements are gastrointestinal upset, including diarrhea; potential vitamin E deficiency when taken for longer periods; and increased LDL cholesterol.

They may also interact with several classifications of drugs, such as aspirin, anticoagulants, antiplatelet drugs and nonsteroidal anti-inflammatories. Adverse effects can result with some blood pressure-lowering medications and with the LDL cholesterol-lowering properties of statin drugs. If you take fish oil supplements, make sure all of your healthcare providers are aware of it.

Using Dietary Supplements Wisely

Dietary supplement manufacturers do not have to prove the safety or effectiveness of their products. Therefore, consumers must be diligent to ensure what they are taking is appropriate and not harmful. Before you start taking supplements, discuss them with a physician, pharmacist or registered dietitian. Provide them with a complete list of what you plan to take, why and how. For instance, replacing a prescription medication with dietary supplements can have repercussions to your care.

Read all label instructions. If you are unsure of an appropriate dosage, discuss it with a physician, pharmacist or registered dietitian. While a specific supplement or dosage may work for one person, it may not work for you. Remember: “Natural” doesn’t always mean “safe.”

Tina Willis, MA, RD, CD, is a registered dietitian at the Indiana Hemophilia &Thrombosis Center.