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Vitamin D is also known as the sunshine vitamin as the body produces it naturally when the skin is directly exposed to the sun.

It’s well known for its role in pairing up with calcium and phosphorus to build and maintain healthy bones and teeth.

Chances are your body is not getting enough, and you could pay a very high price for that

It’s well known for its role in pairing up with calcium and phosphorus to build and maintain healthy bones and teeth.

It also plays an important role in muscle and nerve function, reducing inflammation, cell production and immune function.

In recent years, vitamin D has gained more and more attention for its potential role in the prevention of various conditions and diseases such as cancer, cardiovascular disease, multiple sclerosis, type 1 and 2 diabetes and hypertension.

How much do we need?

Health Canada recommends children and adults (1-70 years) and pregnant and lactating women obtain a daily dose of 600 international units per day, infants (0-12 months) 400 IU and seniors (over 70 years) 800IU per day. These recommendations are based on the requirement to promote the development and maintenance of healthy teeth and bones. Recommendations for disease prevention remain inconclusive.

Where do you find it?

Only a limited number of foods naturally contain vitamin D. Certain fish (salmon, mackerel, swordfish, tuna) are the richest sources, while lower amounts are found in egg yolks and beef liver—but it’s far too difficult to meet the daily recommendation through diet alone.

In the 1930s, rickets (a disease impairing bone formation) affected 80 to 90 per cent of children. This significantly decreased when the government made it mandatory to fortify common foods, such as milk, with vitamin D. Today, the majority of dietary vitamin D is obtained from fortified foods, milk being the primary source. Other foods include fortified milk alternatives such as soy and rice milk, margarine, fortified juices and some breakfast cereals. Canada’s food guide recommends two servings (500ml) of milk or fortified milk beverage a day. According to Statistics Canada, 75 per cent of Canadians who consume one or more servings of milk a day had adequate vitamin D levels, compared to 60 per cent of non-milk drinkers. Read the label—foods and beverages containing at least 15 per cent daily value per serving would be considered a good source.

The sun

The amount of vitamin D we obtain from the sun can be limited by many factors.

• Throughout the colder months there are fewer UV rays and less skin is exposed

• As we age, our body becomes less efficient in converting sunshine to vitamin D

• Clouds and heavy smog block UV rays by 50-60 per cent

• The time of day: UV rays peak between 11a.m. – 3 p.m.

• Darker skin tones naturally have higher protection from the sun’s rays

The recommended intake for vitamin D is based on the assumption of low sun exposure. There is no evidence determining safe levels for UV ray exposure for vitamin D production. Some experts advise against unprotected sun exposure and recommend all vitamin D come from diet or supplement. Others, including the Canadian Cancer Society, stress the importance of limiting sun exposure to no more than a couple of minutes a day. Research shows five to10 minutes a day to the face, arms, legs or back without sunscreen is enough to meet needs.

How much are we getting?

A 2009 Statistics Canada report found that 68 per cent of all Canadians were getting adequate vitamin D, while 32 per cent were below the recommendation. During the colder months, a 15 per cent decrease was observed in those meeting their needs. Children (89 per cent) and seniors (75 per cent) came out on top, while only 59 per cent of individuals between 20-38 years of age had sufficient blood levels. Among the individuals with adequate D levels, 34 per cent were on a supplement.

Then there’s teeth

We often think of calcium as the building block to strong bones, forgetting its vital role in dental development as well. Tooth development begins in the fetus and continues into early 20s. Throughout pregnancy, if the mother is not meeting her calcium needs, her body will leach from her bones to ensure the fetus is properly nourished. In fact, research has shown adequate calcium intake during pregnancy may reduce tooth decay in childhood. As teeth development continues, infants, children and teens should be meeting their daily calcium needs. When these needs are not met, it can result in weak teeth development that’s prone to decay and loss throughout life.

Children between 1 to 8 years of age require 2 to 3 servings of milk and alternatives per day, those 9 to 18 years of age require 3-4 servings.

What’s a serving?

1 cup cow’s milk

1 cup (250 mL) fortified soy beverage or almond milk

1 ½ oz (50g) cheese, block (example: cheddar, mozzarella, Swiss, feta)

1 ½ oz (50 g) cheese, goat

½ cup (125 mL) pudding/custard (made with milk)

¾ cup (175mL) yogourt (plain and flavoured)

200 mL yogourt drinks

Infants younger than one year should stick to breast milk or infant formula, not cow’s milk. Children between one to two years require whole milk due to higher fat needs for brain development and growth. After two years, choose low fat milk and alternatives. All milk contains the same amount of calcium, regardless of fat content.

To supplement or to not supplement?

The need for vitamin D supplementations is a controversial topic.

According to Health Canada recommendations all infants who are breast fed should take 400IU until one year. Formula fed infants do not require a supplement because the formula is already fortified. All adults 50 years and older should take 400IU of vitamin D daily to meet their increased needs. Children and adults who consume two cups (500ml) milk or fortified milk alternative a day do not require a supplement. Consideration should be made for individuals who do not drink milk or milk alternatives, and/or with low blood levels. Those with impaired absorption should also be assessed—they include darker skin tones, conditions such as celiac disease, Crohn’s disease, lower bone density and individuals who are obese.

In contrast, the Institute of Medicine states the current government recommendations are very conservative and don’t provide enough consideration to the most recent findings. Osteoporosis Canada recommends all Canadians take a daily vitamin D supplement because it’s impossible to obtain adequate levels from diet alone. Recommendations include: adults (19-50 years) 400-1,000IU per day and those over 50 years and younger adults at high risk (low bone density) supplement with 800-2,000IU per day. All sources state supplements are safe up to 1,000IU per day.

Too much of a good thing

Too much vitamin D can have adverse effects. The upper tolerable limit for infants is 1,000-1,500IU for infants, children (less than 9 years) 2,500-3,000IU and children (9 years and up), adults and pregnant and lactating women 4,000IU. Toxicity is rare but has been observed in individuals taking a mega dose of 50,000IU over an extended period. It cannot occur from excessive sun exposure or diet. Symptoms include nausea, vomiting, weakness, loss of appetite to more severe kidney damage.

Most importantly, never take a dose beyond the upper tolerable limit without medical supervision. Talk to your doctor, pharmacist and other health care professional prior to taking any supplements. Request to have your vitamin D levels tested to determine if a supplement is needed.

Beyond bones and teeth

Cancer prevention: several studies have revealed a potential link between increased cancer (breast, colon and prostate) risk and low vitamin D. Colon cancer, in particular, has shown the strongest evidence. While, some of the findings look very promising, at this point it cannot be concluded that taking a vitamin D supplement will decrease the risk of cancer.

Cardiovascular disease: several studies have shown that low vitamin D levels may be a contributor to increased heart disease risk. In fact, one study showed men with low vitamin D were twice as likely to have heart disease than those with normal vitamin D. It is thought that vitamin D improves cardiovascular health by decreasing calcium deposits in the arteries and/or decrease blood pressure. More research is needed..

Diabetes: There may be a potential link between vitamin D and the prevention of diabetes (type I & II). One study revealed that women taking 2,000IU per day were 80 per cent less likely to develop diabetes. Conclusive evidence is still needed.

Multiple sclerosis: There’s a higher prevalence of MS in populations living north of the equator compared to the sunnier southern areas, leading to questions as to whether vitamin D plays a role. One study revealed 62 per cent decreased risk of MS in those with adequate vitamin D levels. Another study showed that low vitamin D levels may be associated with the severity of MS symptoms. Again, more research is needed.

Whether you obtain vitamin D through diet, sensible sun exposure and/or supplement, it’s important to ensure you’re meeting the vitamin D recommendations for healthy bones and teeth. The potential benefit of vitamin D in disease prevention requires more research and so far the future looks bright.

RECIPE:

Creamy Dill Salmon

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