Sources of vitamin D

Sunshine - Exposing your hands, face and arms to the sun (in good weather, without sunscreen) for about 15 minutes, three times weekly enables the body to produce what it needs.

Food - Natural food sources of vitamin D include salmon and other ocean fish, and egg yolks. Milk and some bread and cereals are fortified with vitamin D; one cup (250mL) of milk contains about 100 IU. And don't forget cod liver oil.

Supplements - If you suspect you don't get enough vitamin D to aid in calcium absorption, Caltrate 600 with Vitamin D provides 600 mg elemental calcium and 200 IU of vitamin D. Caltrate Plus includes 600 mg of elemental calcium and 200 IU of vitamin D along with other important bone-building minerals such as magnesium, zinc, copper and manganese. Caltrate Plus is also available in fruit-flavoured, chewable tablets and Caltrate 600 with Vitamin D comes in chocolate and vanilla Soft Chews - great for anyone who has a problem swallowing tablets.

When it comes to calcium, whether from food or supplements, the amount absorbed varies between individuals, but generally our bodies use about a third of what we consume. Suggested calcium intakes (e.g. 1200 mg) refer to your intake, not absorption. If you are taking 2 tablets of a calcium supplement, it is useful to take one tablet earlier in the day and take the second later in the day. Supplemental calcium is best absorbed when taken with food. Spacing calcium intake maximizes absorption.

The calcium carbonate used in Caltrate products is about 40% elemental calcium by weight, so just one or two tablets provide recommended daily amounts. People with dietary restrictions should know that the calcium source in Caltrate products is not oyster shell, and Caltrate contains no sugar, lactose, gluten, or alcohol. Caltrate is suitable for sodium-restricted diets.

Quiz: Are you at risk of vitamin D and/or calcium insufficiency?

The mass and density of your bones are affected by hormonal factors, physical activity, and nutrition. In people with bone loss, calcium and vitamin D are the nutrients most likely to be in short supply. If any of the following factors apply to you, you should have your nutritional status for vitamin D and/or calcium assessed by your doctor or dietician.

I don't drink milk daily/have a poor diet.

In Canada, the law requires fortification of all milk for human consumption with vitamin D. One cup (250 mL) contains 100 IU of vitamin D and 300 mg of calcium.

I have dark skin.

Researchers found it took six times as much UV radiation to produce similar amounts of vitamin D in people with dark skin as it did in those with light skin.

I live in a northern climate/get very little sun exposure.

For people who live in a northern climate (above the 40th latitude, which includes almost all of Canada), especially during the winter, vitamin D production may be decreased because of insufficient exposure of the skin to sunlight. There is strong evidence that, during winter, vitamin D is the one nutrient most likely to be insufficient in Canadians.

I have Alzheimer Disease and don't go outside very much. An increased incidence of hip fractures has been observed in Alzheimer patients⁽⁵⁾. One study of women with Alzheimer Disease found that decreased bone mineral density was associated with a low intake of vitamin D and inadequate sunlight exposure.

I have osteoporosis.

Long-term, mild insufficiency of vitamin D is now considered a cause of osteoporosis. A study of women with osteoporosis hospitalized for hip fractures found that 50 per cent had signs of vitamin D deficiency. Supplementation with Vitamin D and calcium has been found to decrease fractures in this high-risk population⁽⁶⁾.

I have a reduced ability to absorb dietary fat (fat malabsorption).

Because vitamin D is carried by, and stored in, the body's fatty tissues, insufficient levels of vitamin D can occur in people with conditions such as pancreatic enzyme deficiency, Crohn's disease, cystic fibrosis, celiac disease (sprue), liver disease, surgical removal of part or all of the stomach, and small bowel disease.

I am a long-term user of corticosteroid medications.

Decreased calcium absorption is a potential side effect of these drugs, and evidence suggests they may also impair vitamin D metabolism, increasing their potential to cause bone loss. Increasing your intake of both calcium and vitamin D through diet or supplementation may help offset these side effects⁽⁷⁾.

^{(1) Dawson-Hughes B, Dallal GE, Krall EA, Harris S, Sokoll LJ, Falconer G. Effect of vitamin D supplementation on winter time and overall bone loss in healthy post-menopausal women. Ann Intern Med 1991; 115:505-512
(2) Chapuy MC, Arlot ME, Duboeuf F, et al. Vitamin D3 and calcium to prevent hip fractures in elderly women. N.Engl.J.Med. 1992; 327:1637-1642
(3) Dawson-Hughes B, Harris SS, Krall EA, Dallal GE. Effect of calcium and vitamin D supplementation on bone density in men and women 65 years of age or older. N.Engl.J.Med. 1997; 337:670-676.
(4) Pfeifer M, Begerow B, Minne HW, Abrams C, Nachtigall D, Hansen C. Effects of short-term vitamin D and calcium supplementation on body sway and secondary hyperparathyroidism in elderly women. J Bone Miner Res. 2000; 15:1113-1118.
(5) Buchner DM and Larson EB. Falls and fractures in patients with Alzheimer-type dementia. J Am Med Associ. 1987; 20:1492-5.
(6) Reid IR. Therapy of osteoporosis: Calcium, vitamin D and exercise. Am J Med Sci 1996; 312:278-86.
(7) National Institutes of Health web site: http://www.cc.nih.gov/ccc/supplements/vitd.html
(8) Nutrition Committee of the Canadian Paediatric Society. http://www.cps.ca/english/statements/II/ii87-01.htm
(9) Source: Dwyer, J. Whitehall-Robins Report, 2000; vol 9, no 4: Nutrients: Essential ingredients for adolescent growth.
(10) Standing Committee on the Scientific Evaluation of Dietary Reference Intakes: Dietary reference intakes: calcium, phosphorus, magnesium, vitamin D, and fluoride. National Academy Press, 1997.}