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Three years ago, in October 2010, we discussed the many benefits of vitamin D. Since that time, the evidence in favour of vitamin D has been growing, and I’d like to provide you with an update.
I’m sure you’re aware that direct sun exposure (to UVB rays) is a major source of vitamin D, but in more northern climates, supplementation is necessary, especially when the days are shorter. There are only sufficient amounts of UV light coming from the sun when the UV index is 3 or higher. |
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It has been estimated that one-third of Americans were at risk of vitamin D inadequacy (24%) or deficiency (8%) according to CDC (Centers for Disease Control and Prevention). This was based on analysis of more than 24,000 people aged 1 or over, surveyed as part of the National Health and Nutrition Examination Survey (NHANES), 2001-2008. The analysis used blood levels of vitamin D set in 2010 by the Institute of Medicine, which defined “at risk of inadequacy” as 30-49 nanomoles per litre (nmol/L). “Deficient” was defined as less than 30 nmol/L.
In Canada, the situation is similar. Analysis of Statistics Canada’s Canadian Health Measures Survey (CHMS), including data collected from 2009 to 2011, showed that just over two-thirds of Canadians (68% had blood concentrations of vitamin D of 50 nmol/L or over, and 32% were below the cut-off – i.e., at risk of inadequacy or deficient in vitamin D.
- Children aged 3 – 5 had the highest rates above the cut-off (89%), whereas those aged 20 – 39 had the lowest (59%).
- Only 34% of Canadians took a supplement containing vitamin D. A larger percentage of those taking supplements were above the cut-off (85%), compared with non-supplement users (59%).
- About 40% were below the cut-off in winter, compared with 25% in the summer.
- On average, women had a higher concentration of vitamin D in their blood than men.
- The percentage of people with adequate vitamin D levels across age groups produced a somewhat U-shaped curve – highest among young children and seniors, and lowest in young adults.
- The body’s ability to produce vitamin D from the sun declines with age. A person aged 70, for example, makes, on average, 25% of the vitamin D that a 20 year old makes when exposed to the same amount of sunlight.
- Other factors affecting absorption of the sun’s rays include latitude, season (and clothing worn), time of day, cloud cover, air pollution, and sunscreen use. In addition, those with darker skin colour do not produce as much vitamin D from the sun.
It’s clear that there’s room for improvement, especially as we find more and more reasons that vitamin D is crucial to our health and well-being. |
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A recap of the major benefits discussed in the October 2010 newsletter
Vitamin D
- Lowers the risk of several types of cancer
- Improves lung function
- Helps build strong bones and teeth
- Contributes to good cardiovascular health by reducing the risk of calcium build-up in the arteries
- Helps our immune systems – note: this is relevant to flu season!
- Combats aging
- Protects against MS (multiple sclerosis)
New information:
Diabetes and insulin resistance
- While we referred briefly to vitamin D’s possible role in benefitting those with type 1 diabetes in the last newsletter, this has become clearer.1
- Low levels of vitamin D may contribute to increased risk of complications in type 1 diabetes.4
- Evidence has also been accumulating that higher levels of vitamin D are important in reducing insulin resistance in people considered to be pre-diabetic with type 2 diabetes, and also preventing and reducing complications of type 2 diabetes.
- Based on some American studies, vitamin D is being considered to possibly prevent type 2 diabetes. This needs to be confirmed in clinical trials.
Falls prevention
- Vitamin D, combined with exercise, has been found to be one of the best ways to reduce the risk of falls in older adults. According to a review of 54 clinical trials including 26,101 participants aged 65 and older, exercise was associated with a 13% reduction in the risk of falling, while trials of vitamin D supplementation saw a 17% reduction in falls.
Parkinson’s disease
- Low serum vitamin D is correlated with increased risk of Parkinson’s disease and further associated with the severity of the disease.
- Mechanistically, vitamin D may protect neurons from stressors although a deficiency does not appear to inherently increase the risk of neuronal damage on the cells associated with Parkinson’s.
- A couple of small studies have suggested that maintaining sufficient levels of vitamin D may help slow the progress of Parkinson’s disease. One study specifically linked the improvement to people with a certain gene. More research is necessary.
Cardiovascular disease
- First, a correction: In the October 2010 newsletter, I quoted a reference stating that vitamin D helped to lower blood pressure. We now know (see our July 2013 newsletter) that it’s the sun’s ability to stimulate the production of nitric oxide that helps to lower blood pressure, not actually its creation of vitamin D.
- Those with insufficient vitamin D levels are significantly more likely to develop heart disease than those who do not.
- Vitamin D insufficiency is associated with increased arterial stiffness and vascular dysfunction in otherwise healthy humans.
Protect your bones, reduce the risk of falling
- Vitamin D supplements of at least 800 IU (International Units) were found to reduce the risk of both hip and non-vertebral fractures, particularly when study participants were compliant in actually taking the supplements. The analysis pooled data from 11 controlled trials, and found that participants who actually took 792 to 2,000 IU of vitamin D daily had a 30% lower risk of hip fracture, and a 14% lower risk of non-vertebral fractures.
Disability prevention
- A new Dutch study reports that 1,962 people aged 55 to 88 were at increased risk of developing limitations in performing everyday tasks if their blood levels of vitamin D (below 20 ng/mL) were low. These tasks included:
- Walking up and down 15 stairs without a rest
- Dressing and undressing
- Sitting down and rising from a chair
- Cutting their toenails
- Walking outside five minutes without resting
- Using personal or public transportation
- The number of disabilities increased from 1 to 2 in those with low levels of vitamin D over a follow-up period of 6 years for the younger participants (under 65) and 3 years for the older participants.
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Mushrooms are a surprising source of vitamin D! While the amount of vitamin D in most mushrooms is too low to make a significant contribution to your daily requirement, brief exposure (15 – 20 seconds) of mushrooms to ultraviolet light can produce more vitamin D than contained in a glass of fortified milk. Mushrooms then provide significant amounts of vitamin D2, not D3 which is more highly recommended; however, findings from a small clinical trial showed that the D2 in mushrooms can boost blood levels of the vitamin as much as supplements.
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What Level of Supplementation of Vitamin D is Appropriate?
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It depends. How much sun exposure do you get? Is your skin colour one that will easily absorb vitamin D from the sun or not? Is it winter or summer, or somewhere in between? What is your age? There is clearly no one answer for everybody. Looking for recommendations isn’t much help either – they’re all over the map, and in my opinion, many are low. On the other hand, it is possible to get too much of a good thing.
The following tables give you an idea of the variation in recommendations for daily and maximum doses.
Recommended daily intakes from various organizations
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Vitamin D Council |
Endocrine Society |
Food and Nutrition Board |
Infants |
1,000 IU/day |
400-1,000 IU/day |
400 IU/day |
Children |
1,000 IU/day per 25 lbs of body weight |
600-1,000 IU/day |
600 IU/day |
Adults |
5,000 IU/day |
1,500-2,000 IU/day |
600 IU/day,
800 IU/day for seniors |
Upper limits set by various organizations
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Vitamin D Council |
Endocrine Society |
Food and Nutrition Board |
Infants |
2,000 IU/day |
2,000 IU/day |
1,000-1,500 IU/day |
Children |
2,000 IU/day per 25lbs of body weight |
4,000 IU/day |
2,500-3,000 IU/day |
Adults |
10,000 IU/day |
10,000 IU/day |
4,000 IU/day |
Very high levels of vitamin D can develop if you:
- Take more than 10,000 IU/day (but not equal to) every day for 3 months or more. However, vitamin D toxicity is more likely to develop if you take 40,000 IU/day every day for 3 months or more.
- Take 300,000 IU in a 24 hour period.
The more you weigh, the more vitamin D your body can handle; the less you weigh, the less vitamin D your body can handle. The above cut-offs of 300,000 in 24 hours, or more than 10,000 IU/day for 3 months or more apply to average adult weight of 125 – 200 lbs.
How much vitamin D is too much for children?
Child’s weight |
Too much vitamin D and potentially toxic amount |
25 lbs or less |
In 24 hours or less |
For over 3 months |
50,000 IU |
2,000 IU/day |
25 – 50 lbs |
100,000 IU |
4.000 IU/day |
50 – 75 lbs |
150,000 IU |
6,000 IU/day |
75 – 100 lbs |
200,000 IU |
8,000 IU/day |
You need to know your blood levels of vitamin D in relation to the supplementation you are currently taking, and adjust it accordingly. If you would like help with this complicated question, please contact me to arrange an appointment.
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Please check out the following Nature’s Sunshine supplements containing vitamin D on our website.
Vitamin D3 1000 IU /store/#!/~/product/id=6402671
Super Vitamins & Minerals /store/#!/~/product/id=6402719
Sunshine Heroes Multiple Vitamin & Minerals /store/#!/~/product/id=6402735
Cal-Mag Plus D /store/#!/~/product/id=6402699
For additional information, please email ramila@ramilas.com; or call Ramilas Healing Arts Clinic at 613.829.0427 for an appointment. Please continue letting friends and family know about this newsletter. Also on our website, please see back issues of this newsletter, additional information about products, order products, and see information about our Clinic.
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- Vitamin D. http://examine.com/supplements/Vitamin+D/ Accessed October 3, 2013.
- 1 in 3 low in vitamin D. Tufts University Health & Nutrition Letter 2011;29(4):3.
- Janz T, Pearson C. Vitamin D blood levels of Canadians. Health at a Glance. Statistics Canada, Catalogue no. 82-624-X, January, 2013.
- Devaraj S, Yun J-M, Duncan-Staley CR, Jialal I. Low vitamin D levels correlate with the proinflammatory state in type 1 diabetic subjects with and without microvascular complications. Am J Clin Pathol 2011;135:429-433.
- Vitamin D a possible tool in diabetes prevention. Tufts University Health & Nutrition Letter 2012;30(4):1,3.
- Exercise and vitamin D rated best bets for preventing falls. Tufts University Health & Nutrition Letter 2011;29(1):1-2.
- Berries linked to lower Parkinson’s risk plus new clues to the disease from ibuprofen and vitamin D. Tufts University Health & Nutrition Letter 2011;29(4):1-2.
- Seaman AM. Vitamin D might help some Parkinson’s patients. Reuters Health, New York, Wed. March 27, 2013 http://www.reuters.com/article/2013/03/27/us-vitamind-parkinson-idUSBRE92Q15L20130327 Accessed October 10, 2013.
- Al Mheid I, Patel R, Munrow J, et al. Vitamin D status is associated with arterial stiffness and vascular dysfunction in healthy humans. J Am Coll Cardiol 2011;58:186-192.
- Higher doses of vitamin D required to protect your bones. Tufts University Health & Nutrition Letter 2012;30(7):1,3.
- Are you getting enough vitamin D to prevent disability? Tufts University Health & Nutrition Letter 2013;31(8):3.
- Mushrooms a surprising source of vitamin D. Tufts University Health & Nutrition Letter 2013;31(6):7.
- Vitamin D Council http://www.vitamindcouncil.org/about-vitamin-d/how-do-i-get-the-vitamin-d-my-body-needs/ Accessed October 21, 2013.
- Vitamin D Council http://www.vitamindcouncil.org/about-vitamin-d/am-i-getting-too-much-vitamin-d/ Accessed October 21, 2013
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The suggestions and recommendations in this newsletter are not intended to be prescriptive or diagnostic. The information is accurate and up to date to our knowledge, but we are not responsible for any errors in our sources of information. |
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These newsletters will help you make better choices for better health. The choices that you make today can either have a positive or negative impact on your overall health. Begin by choosing better. It is a step toward longevity.
Sincerely,
Ramila Padiachy
Ramila's Healing Arts Clinic
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