A healthy individual who carries a diagnosis of asthma does not ordinarily require nutritional supplements on account of his or her asthma. Asthma is a respiratory condition and does not affect your body’s ability to absorb nutrients from foods. It is important to take your asthma treatment as prescribed by your physician, to exercise, and aim to keep your body weight in a healthy range by eating a well-balanced and nutritious diet.
A healthy adult with asthma who eats a balanced, healthful diet will derive no additional lung benefit from taking vitamin or mineral supplements.
Specific clinical circumstances may require consideration of vitamin and mineral supplementation. Examples include:
Pregnancy (may need folic acid for example, multivitamins, possibly iron)
Osteopenia & osteoporosis (may need extra calcium and vitamin D)
Food allergies that mandate elimination of a food group from the diet
Vegetarian diet (may require iron in some cases)
An exclusively breast-fed baby (will require vitamin D supplementation)
Persons aged 65 years and older
Persons with restricted calorie intake (less than 1,200 calories a day)
Persons with medical conditions (not asthma!) resulting in malabsorption of nutrients
As a general rule:
More vitamin and mineral supplements are not necessarily better or more healthful.
Excess intake of fat-soluble vitamins over time can cause toxic effects.
Before taking any vitamin or mineral supplements, check to make sure that they will not interact adversely with your “regular” maintenance medicines or any other prescription medicine you are taking.
Your physician is a good source of medical advice regarding diet and dietary supplements; consultation with a registered dietitian (RD) may also be helpful.
Dietary recommendations for persons with-out asthma obviously apply as well to individuals who also have asthma. The vitamins required for health are found in the foods we eat, with some vitamins being more abundant in the diet than others. Healthful levels of vitamin D, discussed in more detail later, may in particular be difficult to obtain from natural sources alone. A vitamin tablet you purchase in the store is synthesized in a pharmaceutical laboratory, “copied” in a sense from the vitamins extracted from food and found in nature.
Supplements should never replace good eating habits and healthful food selections. Many foods in the American diet are additionally fortified with vitamins and nutrients. Vitamin D, for instance, been added to milk sold in the United States since the 1930s, in response to childhood rickets, a major childhood public health problem then.
Vitamin deficiencies in our society are usually due to an illness (often of the intestinal tract or excretory system) that interferes with the body’s ability to absorb the required vitamins present in food, rather than a vitamin deficiency in the diet or food itself.
A closer review of vitamins reveals that there are two categories of vitamins: fat-soluble vitamins and water-soluble vitamins. Fat-soluble vitamins include vitamins A, D, E, and K. If taken in amounts exceeding the body’s immediate requirements, the extra fat-soluble vitamins are stored in the body’s fatty tissues. If still more fat-soluble vitamins are ingested, vitamin toxicity can develop.
Water-soluble vitamins, on the other hand, are not stored by the human body. The B vitamins and vitamin C are examples of water-soluble vitamins. If you take a tablet of vitamin C, most of it is eliminated in your urine. Your body absorbs what it requires, and the kidneys excrete the rest. Since the majority of the dose of the water-soluble vitamins Americans add to their diet in pill form ends up in their urine, many nutritionists joke that Americans have the healthiest and most expensive toilet bowl water in the world!
The U.S. National Academy of Sciences’ National Research Council has established guidelines on the amount of various nutrients men and women should eat at different ages. The guidelines constitute the Recommended Dietary Allowances, or RDAs—often referred to as “Recommended Daily [sic] Allowances.”
In 1997, the U.S. Institute of Medicine’s Food and Nutrition Board (FNB) published an updated report that modified recommendations for calcium, Vitamin D, fluoride, magnesium, and phosphorus, and eliminated the name RDA in favor of Dietary Reference Intakes (DRIs). Most healthy persons with good eating habits easily meet the DRIs.
Adequate calcium intake is especially important in growing girls and in all teenagers. Many young people drink soda daily, often at mealtimes. The large amounts of soft drinks consumed by adolescents at the expense of milk may be one factor responsible for their increasingly inadequate calcium intake.
The Institute of Medicine of the U.S. National Academy of Sciences has also added a new category, tolerable upper intake levels (ULs), to caution against excess intake of nutrients such as vitamin D that can be harmful in large amounts. You can access the latest detailed recommendations through its Web portal at http://dietary-supplements.info.nih.gov/ .
What if you don’t quite fit into the healthy adult with asthma eating a balanced diet category described previously? There are, of course, specific circumstances that may lead your physician to advise you to regularly supplement your diet with a multivitamin tablet or minerals. Those situations are not asthma related. For example, all pregnant women should take a folic acid supplement to help prevent neural tube defects in the developing fetus.
So, it goes without saying that the recommendation for folic acid supplementation also applies to pregnant women with asthma. As this books goes to press, prior recommendations about vitamin D are undergoing intense review (Table 47). Our body obtains vitamin D from direct skin exposure to sunlight and from food in our diet.
Fish oils and the flesh of fish such as salmon, tuna, and mackerel are naturally rich in vitamin D. Small amounts of vitamin D are found in beef liver, cheese, and egg yolks as well. Other food that does not naturally contain vita-min D will have it added, as in cow’s milk, as mentioned previously. According to the National Institute of Health’s Office of Dietary Supplements, “In the United States, foods allowed to be fortified with vitamin D include cereal flours and related products, milk and products made from milk, and calcium-fortified fruit juices and drinks.
Maximum levels of added vitamin D are specified by law.” Identification of groups of people at risk for vitamin D deficiency, recognition of wide-ranging adverse health outcomes from vitamin D deficiency, and determination of appropriate and safe supplementation strategies are the focus of active research. Recent developments are summarized in Table 47.
In 2008, the American Academy of Pediatrics (AAP) issued recommended intakes for vitamin D that exceed those of the Food and Nutrition Board. “Prevention of Rickets and Vitamin D Deficiency in Infants, Children, and Adolescents,” published in Pediatrics, the journal of the American Academy of Pediatrics, advised vitamin D supplementation for all breast-fed infants and for youngsters and teenagers who do not obtain 400 I.U. daily of vitamin D through their diet.
The Food and Nutrition Board then established an expert committee in 2008 to review the DRIs for vitamin D and calcium to determine safe upper limits for both and revise, if necessary, the DRIs last published in 1997. The updated Food and Nutrition Board report is expected in May 2010.
Of particular importance for the reader is the person with severe food allergy who requires the elimination of an entire food group. A child with a peanut allergy does not need to compensate for the lack of peanuts in his diet, for example, but another child unable to drink milk or eat cheese certainly should be placed on calcium supplements to ensure an adequate intake of calcium.
Finally, if your calorie intake is reduced or limited (by dieting or loss of appetite) below 1200 calories (as a general cut off ), you probably should take a multivitamin and mineral supplement on a regular basis. Be sure to check with your doctor if you think you may require vitamin or mineral supplements.