Test Your Knowledge

As the name implies, dietary supplements are intended to supplement and not replace food from the diet. Supplements are not considered a food or a drug. Energy bars or high-calorie, fortified treats may be considered a supplement when they are represented to be the sole item of a meal or diet. Most importantly, supplements are required by the U.S. Food and Drug Administration to be labeled a “supplement.”

Supplements contain one or more dietary ingredients intended to provide nutritional value to the human body. New dietary ingredients are those sold in the United States after October 1994 (when the Dietary Supplement Health and Education Act was enacted), and are subject to additional regulations.

Generally, healthy people who eat a variety of foods do not need supplements. Diets high in fiber, low in fat, that include a variety of fruits and vegetables (five to nine servings per day) and whole grains provide a balanced level of nutrients for most people.

However, the use of supplements may be recommended in some cases. These may include:

• Insufficient dietary nutrients. People who consume too little food (e.g., less than 1,200 calories per day), too small a variety of foods or engage in poor dietary choices (e.g., diets high in fast foods or processed foods) may not get enough nutrients through diet alone. In addition, vegetarian diets may result in deficiencies of calcium, iron, zinc and vitamins B12 and D, depending on the categories of foods not consumed.
  
  
• Medical conditions that affect nutrient absorption, use or excretion. Allergies or certain food intolerances (e.g., lactose intolerance) may result in specific nutritional deficiencies (e.g., calcium). Difficulty absorbing nutrients can result from a variety of disorders, including liver, gallbladder, intestinal (e.g., Crohn’s disease) or pancreatic diseases. Surgeries affecting the digestive tract and certain medications may also affect nutrient absorption, use or excretion.
  
  
• Pregnancy. Women may need more of certain nutrients during pregnancy (e.g., calcium, folate and iron). Adequate levels of folate are important before and early in pregnancy to reduce the risk of certain birth defects (e.g., spina bifida). Iron is also important during pregnancy to help prevent fatigue.
  
  
• Menopause. Women going through menopause may require extra nutrients, due to a drop in levels of the hormone estrogen. Calcium and vitamin D supplements may help reduce the risk of osteoporosis in these cases.
  
  
• Heavy menstrual bleeding. Women who lose significant amounts of blood during menstruation may experience an iron deficiency, which can lead to anemia.
  
  
• Old age. Older adults may experience a lack of adequate nutrition due to reduced appetite. This may occur in conjunction with a variety of illnesses that are more prevalent among older adults. Ill-fitting dentures as well as hormonal or other biological changes can result in a loss of adequate nutrients among older adults.
  
  
• Smoking. Tobacco hinders the absorption of many different types of vitamins and minerals (e.g., vitamin C, folate, magnesium, calcium). People who smoke may benefit from certain types of supplements.
  
  
• Excessive drinking. Consuming alcohol in large quantities over a long period of time can impair digestion and the absorption of certain vitamins and minerals (e.g., vitamin B1, iron, zinc, magnesium, folate). Excessive drinking has been defined as more than two drinks per day for men under 65 and more than one drink per day for all women or men over 65.
  
  
• Limited dairy product consumption or sun exposure. People who do not or cannot consume milk, or who do not receive at least 10 to 15 minutes of exposure to sunlight per day may not receive enough vitamin D.  

The use of supplements is widespread. Tens of thousands of products in the United States are marketed as dietary supplements. Multivitamins and minerals that contain a variety of dietary ingredients make up the largest proportion of these products.