Dr. Irfan Qureshi, ND

Recently, there has been conflicting advice about supplementing with vitamin D. Vitamin D is a nutrient that is necessary for overall health and helps to optimize the function of a number of different body systems. However, past research on vitamin D points to possible side effects from excessive intake.

Vitamin D is a fat-soluble vitamin obtained from our diet and also manufactured in the body from exposure to sunlight. A major function of vitamin D is to maintain calcium balance in the body. In this respect, it is important for nerve function and maintaining healthy bones. Research also points to powerful effects of vitamin D on the immune system. Adequate vitamin D levels protect against certain autoimmune diseases. Studies show that sufficient vitamin D intake helps prevent diseases such as multiple sclerosis (MS) and rheumatoid arthritis.

Vitamin D may also help prevent certain cancers, including those of the breast, colon and prostate. Beyond this, research shows benefits of vitamin D in regulating blood glucose and blood pressure.

Most of us don't get enough vitamin D from our diets and those of us living in northern climates don't get enough sun exposure. Many individuals are, therefore, at risk of having low levels of vitamin D and probably could benefit by supplementing with this vitamin. Other risk factors for vitamin D deficiency include dark skin, aging, problems absorbing fatty foods, digestive conditions and being overweight. More and more research continues to point to an increased need for vitamin D to maintain optimal health. Research suggests that 800 to 1,000 IU of supplemental vitamin D per day are required for adults living in northern climates (such as ours) to maintain optimal levels of this vitamin.

Concerns have been raised about possible toxicity with too much vitamin D. However, the concerns are unfounded at levels that are commonly supplemented. The Institute of Medicine had earlier set the tolerable upper limit for adults at 2,000 IU (international units) per day. The latest research suggests that these levels may be too conservative and that toxicity is unlikely in healthy adults at intakes of up to 10,000 IU per day. Given the many health benefits of vitamin D and its high level of safety, it seems prudent that all adults should supplement with a minimum of 400 to 800 IU per day. The elderly and those with additional risk factors for deficiency should consider taking higher amounts.

Dr. Qureshi is a naturopathic physician specializing in the treatment of chronic health issues. He currently practices at Pacific Highway Natural Medicine in SeaTac. He can be reached at(206) 923-7600.