To D or not to D, that is the question.
The history of rickets from Vitamin D deficiency dates back to 200 A.D. Fast-forward to the 1640’s, and it was a common bone disease in England. It wasn’t until the 1930’s that public health agencies recommended adding “D” to the diets of infants and children. After this, the incidence of rickets leveled off. Unfortunately, rickets has resurfaced. Rickets manifests as bowed legs, dental deformities, and rib cage abnormalities.
The Sunshine Vitamin
Vitamin D is fond of calcium and phosphorus. This trio of nutrients is necessary for bone formation. Vitamin D can be obtained through sun exposure. For this reason, it’s been nicknamed “the sunshine vitamin.” To meet the body’s need for Vitamin D, you need 10-15 minutes of sunshine, three times weekly. The sun must target the skin of your face, arms, legs, or back, without sunscreen. The exact exposure time varies by age, skin type, time of day, and season.
NOTE: The rays of natural sunlight that produce vitamin D in your skin cannot penetrate glass. Therefore, you cannot get Vitamin D inside a car or building.
Who’s At Risk For Deficiency?
Although it’s easy to get Vitamin D from the sun, deficiency is common. During winter, people in Canada and the northern US don’t get enough sun due to shorter daylight hours. So people living in “the north country” may especially need to focus on foods with Vitamin D.
Older adults and dark-skinned folks may also be unable to make enough D from the sun. They have fewer skin receptors for converting sunlight to Vitamin D. In the elderly, other contributing factors are aging kidneys, decreased absorption, and malnutrition. Statistics show that 40% of elders in sunny climates, such as Florida, don’t have enough D in their systems.1
Certain disease conditions pose a greater risk for deficiency, such as cancer, heart disease, rheumatoid arthritis, and multiple sclerosis. Lack of adequate D can also lead to depression. Deficiency has been linked to asthma, diabetes, high blood pressure, colitis, cystic fibrosis, and Alzheimer’s disease.
Infants may not get sufficient Vitamin D if they’re breastfed, and moms don’t give a Vitamin D supplement. Pregnant women may also not get enough D in their diets.
CAUTION – Although a little sun has a lot of benefit, you don’t want to overdo it. You should apply sunscreen when you’re outdoors for more than 15 minutes, to protect against skin cancer.
Symptoms of Deficiency
Your body may signal a deficiency with bone pain, muscle weakness, fatigue, and frequent infections. The way to definitively know if you’re deficient is to see your doctor and have a blood test. If you have health insurance, find out if payment for the “25(OH)D test” is provided. If coverage is confirmed, see your primary care physician, and ask for the 25(OH)D test. There’s another test called a “1,25(OH)₂D test,” but it won’t indicate if you’re low in D. According to the Vitamin D Council, if a test reveals a level below 30 ng/ml, you need more D.
Vitamin D’s Starring Role
Vitamin D’s primary role is in bone formation. However, it is also necessary for proper muscle, heart, and brain function. It promotes healthy lungs. It protects against infection and cancer.
Foods With Vitamin D
Certain foods are a good source of Vitamin D. Two Vitamin D dynamos are:
- Salmon – 3 ounces of canned sockeye has about 650 IU (International Units), more than you need in one day.
- Mushrooms – where packaging reads “High Vitamin D,” this means the mushrooms have been treated with UV light at the end of harvest. Three ounces of UV-treated mushrooms can provide 400 IU.
Other Vitamin D all-stars are:
- Light tuna canned in water – 3 ounces packs 154 IU, about 30% of the dietary reference intake (DRI).
- Sardines canned in oil – 2 sardines log 46 IU, about 13% of the DRI.
- Fortified milk and yogurt – values vary according to quantity and brand.
- Egg yolks – one large yolk has 37 IU.
- Vitamin D-fortified orange juice – refer to Nutrition Facts Label.
- Fortified ready-to-eat breakfast cereal – refer to Nutrition Facts Label.
Vitamin D Supplementation
If you can’t get enough sun exposure and have dietary limitations, you can take a Vitamin D supplement. There are three main authorities that make recommendations for daily intakes: the Vitamin D Council, Endocrine Society, and Food and Nutrition Board. Their suggested levels vary. To avoid overdosing on Vitamin D, which is toxic, aim for the Food and Nutrition Board’s daily levels, which are:
- Infants – 400 IU
- Children – 600 IU
- Adults – 600 IU; 800 IU for seniors
The Food and Nutrition Board numbers are the official recommendations by the US Government. You may wonder why there is such variation in recommendations. This is because researchers are still studying optimal levels.
Vitamin D supplements come in two forms, D2 (ergocalciferol) and D3 (cholecalciferol). Vitamin D3 is considered the best type to take. It is the form produced in our skin when exposed to UVB light from the sun.
Vitamin D Toxicity
Vitamin D is a fat-soluble vitamin. Unlike water-soluble vitamins that are eliminated in urine, Vitamin D is stored in fatty tissue. Remembering that the body produces Vitamin D from sunlight, and food contains Vitamin D, you can see how toxicity is possible. The Food and Nutrition Board has set the safe upper limits for Vitamin D supplementation at:
- Infants – 1,000-1,500 IU/day
- Children – 2,500-3,000 IU/day
- Adults – 4,000 IU/day
To avoid toxicity, the Vitamin D Council advises getting your Vitamin D level tested every 3 months. When a blood level of D is too high, there will be a corresponding high level of calcium, known as hypercalcemia. A 25(OH)D level above 150 ng/ml is potentially toxic. If both D and calcium levels are high, you’re getting too much vitamin D. Symptoms of hypercalcemia are:
- excessive thirst
- frequent urination
- loss of appetite
- diarrhea or constipation
- abdominal pain
- muscle pain or weakness
Vitamin D and Disease Treatment
The Vitamin D Council has a wealth of valuable information on Vitamin D and disease. In its online “Health Conditions” section, you can look up the latest Vitamin D research and recommendations for specific diseases. Summaries are available on 45 medical conditions. For example, you can look up the most recent findings on Vitamin D and depression, diabetes, eczema, and influenza. To access the Vitamin D Council’s summaries, go to: http://www.vitamindcouncil.org/health-conditions/#, or click here:
To D or not to D depends on many factors, including your age, locality, and ethnicity. Certain diseases create a risk for deficiency. Can you get enough Vitamin D from sunlight and food? The Vitamin D Council says it’s not likely.
So here’s the bottom line:
- Aim for 10-15 minutes of sunshine, 3 times a week.
- Include the following in your diet: salmon, treated mushrooms, light canned tuna, sardines in oil, and egg yolks. You can also get your D from fortified milk, yogurt, OJ, and cereal.
- Supplement with no more than 400 IU of Vitamin D3 daily, unless blood testing shows a deficiency.
- Stay tuned to the news for the most current research on Vitamin D. The benefits of Vitamin D for disease treatment continue to be studied.
One thing you can be sure of — the “sunshine vitamin” is vital for your health!