Vitamin D A dose of sunshine goes a long way
Calcium and vitamin D: The dynamic duo
Who’s at risk?
• African Americans – melanin reduces the skin’s ability to make vitamin D
• Those with limited exposure to sunlight
• Breastfed infants – mother’s milk does not contain enough vitamin D
• Elderly – less able to convert vitamin D to its active form
• Vegetarians that follow a strict plant-based diet
• People with certain intestinal problems, such as celiac disease
• Obese people – excess fat impedes the circulation of vitamin D
Want to know the score?
The 25-hydroxy vitamin D test measures the level of vitamin D in the body.
Vitamin D Status Deficient Insufficient Sufficient |
Value Less than 20 nanograms/milliliter (ng/mL) 20 to 29 ng/mL 30 ng/mL or more |
The Vitamin D Council recommends a minimum reading of 50 ng/mL
 National Institute of Arthritis & Musculoskeletal & Skin Diseases Several studies suggest that normal levels of vitamin D are required to reduce the risk for many chronic illnesses, such as:
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So many choices
Calcium can also be obtained through supplements, but the trick is to determine which one. There are many choices — carbonate, citrate, lactate, gluconate. Here are some helpful tips.
• Calcium carbonate contains the most calcium per pill (40 percent), but should be taken after meals.
• Calcium citrate contains less calcium per pill (20 percent), but does not need to be taken with food.
• Determine the amount of “elemental calcium” — the amount available for the body to absorb and what’s counted in the recommended daily dose of calcium. If not specified, check the Nutrition Facts label. The amount of elemental calcium will be listed in milligrams (mg) according to “serving size” — generally one or two tablets.
• Gluconate and lactate contain low content of elemental calcium, and would require several tablets to meet the calcium requirement.
• Avoid dolomite, oyster shell and bone meal calcium. They might contain metals and lead.
• Look for USP (United States Pharmacopeia) symbol on the package, which designates standards for quality and purity.
• If the symbol is not listed, you can test the quality of pill by dissolving it in clear vinegar. Stir occasionally. If the pill dissolves within 30 minutes, it will also dissolve in your stomach.
Where’s the calcium? |
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Calcium is found in dairy products including yogurt, cheeses and milk; to reduce fat intake try skim milk or low fat products. |
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Dark, leafy green vegetables such as spinach, kale, collard greens, and broccoli are all good sources of calcium. These foods are great in salads, stir-fries or even on their own.
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Seafood like sardines, pink salmon, ocean perch, blue crab, clams and rainbow trout can be a tasty way to up your intake. |
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A closer look
| Vitamin D deficiency and insufficiency are common in young people. So much so that rickets, or bone weakness, has made a comeback. Rickets is seen more frequently in black children often due to less time playing outdoors and low consumption of dairy products particularly in those who are lactose intolerant. Teens who favor soft drinks and iced teas over fortified milk and cereal are also hard hit. The American Academy of Pediatrics recently revised its guidelines and now recommends a minimum daily intake of 400 IU of vitamin D beginning soon after birth and continuing through adolescence. |
Questions & Answers
Lisa Michelle Owens, M.D.
Medical Director
Brigham Primary Physicians at
Faulkner Hospital
1. Why does obesity increase the risk of vitamin D deficiency or insufficiency?
Vitamin D is a fat soluble vitamin which means it is stored in our fat cells. As our weight and percentage of body fat increase, vitamin D levels fall. Overweight individuals appear to deposit some of their vitamin D in their excessive fatty tissue, making it more difficult to raise their vitamin D levels. Studies have shown that obese people tend to obtain lower levels of vitamin D — even when exposed to ultraviolet light or when taking vitamin D supplements.
2. Why are vitamin D supplements necessary for breastfeeding babies?
Breastfeeding babies get their milk from their mom and human milk does not have adequate amounts of vitamin D to meet the needs of a growing baby.
3. What’s the best source of vitamin D for vegetarians?
Depending on the foods they embrace, vegetarians can get vitamin D from foods fortified with vitamin D, such as cow or soy milk, yogurt, orange juice and certain cereals. Vitamin D supplements and sun exposure are also opportunities for boosting vitamin D levels in those who do not eat fish.
4. Why does vitamin D deficiency increase during the winter in northern cities?
Vitamin D insufficiency or deficiency increases during the winter months because of the increased prevalence of overcast days and the reduced strength of ultraviolet B rays — the major source of vitamin D development. The significant decrease in sunlight results in dramatic decrease in the activation of vitamin D in our skin.
5. If a person prefers to avoid the sun, is it possible to obtain adequate levels of vitamin D through the diet?
Yes, but the amounts required may be excessive. Milk and orange juice are classic beverages fortified with vitamin D. Yogurt is often fortified with vitamin D as well. It is important to note that cheese, which is a good source of calcium, does not contain high amounts of vitamin D. Oily fish, such as salmon and mackerel, is the best natural source of vitamin D in the diet.
6. Is there a risk of getting too much vitamin D?
Vitamin D toxicity is rare and occurs only with very excessive use of vitamin D supplements. It is not possible to get too much vitamin D from the sun. Toxic levels of vitamin D can cause nonspecific symptoms such as nausea, vomiting, poor appetite, constipation, weakness, and weight loss. More serious side effects include elevated blood levels of calcium, causing mental status changes such as confusion and heart rhythm abnormalities.
7. What’s the difference between vitamin D2 and vitamin D3?
When people have very low levels of vitamin D, or are considered deficient, doctors will prescribe high doses of vitamin D2 (available by prescription only) to take once a week for a few months. The dose is usually 50,000 International Unit (IU). When levels improve, doctors then switch them to once daily vitamin D3, which is available as an over-the-counter supplement. If a person has mildly low levels of vitamin D, or are considered insufficient, doctors will start them on daily vitamin D3 from the very beginning. The supplements typically are sold in doses of 1,000 to 2,000 IU.