In Brief

Vitamin D plays a central role in the prevention of different inflammatory and chronic diseases. Consuming 1,000–4,000 IU (25–100 mcg) of vitamin D3 daily should be ideal for most people to sustain good health. It is generally recommended that people with vitiligo keep their vitamin D levels in the mid-upper range of normal. 

One study suggests that a high-dose vitamin D therapy may be safe and effective in reducing vitiligo activity. Sixteen patients with mostly darker skin type were given 35,000 IU daily for six months, combined with restriction of dairy products and calcium-enriched foods, and minimum hydration of 2.5 L daily. As a result, fourteen of them had repigmentation ranging from 25 to 75%. It remains unclear whether long-term, high-dose supplementation provides any benefits to patients with vitiligo.

Keep in mind that vitamin D supplements have the potential to interact with several types of medications, such as corticosteroids, anti-epileptic and weight-loss drugs. Ask your doctor whether a vitamin D supplement might benefit you before making any dietary changes.  

Vitamin D Basics

Known as the "sunshine vitamin," vitamin D is produced by our bodies as a result of sun exposure. Sunlight also triggers the release of a number of important compounds in the body, including serotonin and endorphins. They improve circadian rhythms, fight infection, reduce inflammation, dampen autoimmune response, reduce the risk of prostate and other cancers; they also improve virtually every mental condition. These seem like benefits everyone should take advantage of, yet this is often not the case and vitamin D deficiency is incredibly common. 

Modern lifestyle and environmental conditions are blamed for vitamin D insufficiency in aprroximately 42% of people of adults in USA; this number rises to a staggering 82% of black people and 70% of Hispanic people. Symptoms of vitamin D deficiency are often subtle and non-specific, and most people are unaware of it. You may be at risk of deficiency if you live in northern latitudes, adhere to a strict vegan diet, dark skinned, have certain medical problems, are overweight, or spend most of your time indoors.

People who have these medical conditions that reduce fat absorption are also prone to vitamin D deficiencies:

• irritable bowel disease (IBD)
• Crohn's disease
• liver disease,

and also people who have had bariatric surgery.

The importance of maintaining an adequate vitamin D status is beyond any doubt, however, there is no consensus on vitamin D levels required for optimal health. Each person’s needs vary so much with age, underlying health conditions, season, latitude, skin color, personal history, philosophy, and so much else that it’s impossible to provide a one-size-fits-all recommendation.

The U.S. National Institutes Of Health recommends a dietary allowance of vitamin D for children 1 to 18 years and adults through age 70 years is 600 international units (IU); it increases to 800 IU daily after age 71 years. A body of current research suggests that consuming 1,000–4,000 IU (25–100 mcg) of vitamin D daily should be ideal for most people to sustain good health.  

Source of Vitamin D

Two main forms of vitamin D in the diet are:

• Vitamin D2 (ergocalciferol), it comes from plant foods like mushrooms
• Vitamin D3 (cholecalciferol), it comes animal foods like salmon, cod and egg yolks.

Vitamin D3 is almost twice as potent as D2 in raising blood levels of vitamin D. 

To meet the recommended daily allowance (RDA) vitamin D level, get regular sun exposure and choose foods that are rich in vitamin D:

• Cod liver oil, 1 tablespoon: 1,360 IU or 340% of the RDA
• Swordfish, cooked, 3 ounces: 566 IU or 142% of the RDA
• Salmon (sockeye), cooked, 3 ounces: 447 IU or 112% of the RDA
• Tuna fish, canned in water, drained, 3 ounces: 154 IU or 39% of the RDA
• Orange juice fortified with vitamin D, 1 cup (check product labels, as amount of added vitamin D varies): 137 IU or 34% of the RDA
• Milk, nonfat, reduced fat, and whole, vitamin D-fortified, 1 cup: 115-124 IU or 29-31% of the RDA
• Yogurt, fortified with 20% of the DV for vitamin D, 6 ounces (more heavily fortified yogurts provide more of the DV): 80 IU or 20% of the RDA
• Sardines, canned in oil, drained, 2 sardines: 46 IU or 12% of the RDA
• Liver, beef, cooked, 3 ounces: 42 IU or 11% of the RDA
• Egg, 1 large (vitamin D is found in yolk): 41 IU or 10% of the RDA
• Ready-to-eat cereal, fortified with 10% of the DV for vitamin D, 0.75-1 cup (more heavily fortified cereals might provide more of the DV): 40 IU or 10% of the RDA
• Cheese, Swiss, 1 ounce: 6 IU or 2% of the RDA.

Source: National Institutes of Health. The U.S. Department of Agriculture’s (USDA’s) FoodData Central lists the nutrient content of many foods and provides a comprehensive list of foods containing vitamin D arranged by nutrient content and by food name. 

"Fortified foods" provide most of the vitamin D in the American diet nowadays. For example, almost all of the U.S. milk supply is voluntarily fortified with 100 IU/cup. In Canada, milk is fortified by law with 35–40 IU/100 mL. Ready-to-eat breakfast cereals often contain added vitamin D, as do some brands of orange juice, yogurt, margarine and other food products. 

Interactions with Medications

Vitamin D supplements have the potential to interact with several types of medications:

• Corticosteroid medications, such as prednisone, can impair vitamin D metabolism
• Both the weight-loss drug orlistat (brand names Xenical® and alliTM) and the cholesterol-lowering drug cholestyramine (brand names Questran®, LoCholest®, and Prevalite®) can reduce the absorption of vitamin D
• Both phenobarbital and phenytoin (brand name Dilantin®), used to prevent and control epileptic seizures, increase the hepatic metabolism of vitamin D to inactive compounds.

If you're taking any of these medications on a regular basis, discuss this with your doctor.