As we head into the fall and winter months with less sunshine it's important to make sure you are meeting your vitamin D requirements. As a dietitian at Healthy Steps assessing a client’s supplement needs is part of what I do. Too little vitamin D can lead to calcium and phosphorus levels in the blood to decrease, which can lead to weak bones. Children need vitamin D to build strong bones and prevent rickets. For adults, Vitamin D is an essential assistant to osteoporosis (porous bones) prevention and treatment. But it doesn’t just stop here, there is emerging evidence that suggests that vitamin D plays a role in the immune system and that it’s involved in maternal cell and tissue growth. There is also some evidence that vitamin D may play a preventative role in some types of cancer, particularly colorectal and breast cancers. Observational studies have found vitamin D deficiency to be associated with a higher risk of dementia and to be associated with poorer cognition among middle- to older-aged adults without dementia. There is accumulating evidence suggesting that vitamin D deficiency might be involved in insulin resistance and PCOS (polycystic ovarian syndrome). This is just some of the mounting evidence that vitamin D plays a vital role in keeping us healthy.
Where can we get vitamin D from?
But are we getting enough from the sun and from food?
The answer depends on some factors some of which include age, time of year, adequate intake of vitamin D food sources if a person is above ideal weight, skin pigmentation, risk of osteoporosis and if a person has a condition that may impact vitamin D absorption.
Let’s focus on two of these factors. Our bodies make vitamin D when our skin is exposed to sunlight hence the name “the sunshine vitamin” but in Canada, we get less sunlight from October to April. We tend to spend less time outside and we are usually covered up when we do go outside during the winter months and/or wearing sunscreen. Based on this, it is unlikely we will meet our needs from the sun during these months, therefore a supplement is a good idea. Age is a factor because as we age our skin’s ability to absorb vitamin D declines. The recommendation for adequate intake for ages 1-70 is 600 IUs and for adults >70 it is 800 IU’s.
What about foods, what foods contain vitamin D, are we getting enough from our food?
Foods such as salmon contain natural sources of vitamin D (75 g serving has 395 IU’s), fortified foods such as 1 cup of cow’s milk and milk alternatives have ~103 IU’s, yogurt ~82IU’s (however not all yogurts are fortified) and 1 teaspoon of margarine will have ~30IU’s. So, as you can see it can sometimes be challenging to ensure we are having adequate vitamin D intake and for the >70-year-old population it is not likely that they will meet the higher requirements.
Who needs a supplement?
Health Canada recommends those >50 years old supplement with 400 IU’s daily to meet basic requirements. Although, I would like to mention that other medical associations recommend higher amounts. It is also recommended that exclusively breastfeed infants be supplemented with 400 IUs per day. With this guideline in mind upon assessment, I find many adults and children not meeting their dietary intake. In addition to many having limited sunlight exposure especially in the winter, therefore requiring higher supplementation. In general, I often recommend adults take 1000 IUs per day especially in the winter and 1000-2000 IUs for adults >70 years old all year round. If an individual is found deficient after taking a blood test, they will require higher amounts specific to their deficiency. What about kids? The fact is that kids are not always meeting their dietary requirements as I mentioned above so taking 400 IUs per day in the winter months can be a good idea. These are safe amounts to take, however too much vitamin D can be harmful and can lead to depositing too much calcium in the bones which can be dangerous so do talk to your dietitian or doctor if you are wondering or doctor if you are wondering if you need to take higher amounts then I mentioned above. As a dietitian at Healthy Steps, I offer consultations to assess your diet that includes promoting the increase in vitamins and minerals through foods first and when there is a need to optimize health, I recommend supplementation.