Photo thanks to Harvard University
Many of my clients have had blood tests and found that they are Vitamin D deficient, not suprising since we live in the Southern Highlands of NSW where bad weather is more likely than good. My Sydney based family then decided to have blood tests to see what their Vitamin D levels were like, and found out due to our Eurasian descent, we do not absorb vitamin D well at all. I am pearly white, but my heritage, the same one that stops me from burning in the sun, also stops me from absorbing as much Vitamin D as my other half who is from the UK.
The most natural way to receive enough vitamin D is to spend 20 to 40 minutes a day in the sun. Face and arms unprotected by clothing. Sorry, but I am so not sticking my face in the sun, all my training tells me to keep it out! So, I stick my pearly white legs in the sun instead. But, some days, there is no sun, and or, it is too hot!
There are some amazingly good natural sources of Vitamin D which, along with the sun, (the sun is still the best source of D) will help you keep your vitamin D levels up.
But you ask, why do I need vitamin D? Is this some crazy fad like the Atkinson Diet? Unfortunately it is not, there has been a lot of research done since the 1990s proving that Vitamin D is a major player in many of our health issues.
Lets first look at Vitamin D, I have found there is more to it than we are lead to believe;
Up until the mid-1990’s, the answer to the vitamin D question would have been fairly simple: it is a fat-soluble vitamin needed to prevent a bone disease in children called “rickets.” Previous studies going back to the early 1800’s determined that cod liver oil could help to prevent and cure particular problems with bone development in children. In the early 1900’s, a compound called “fat-soluble factor D” was isolated from cod liver oil, and this factor turned out to be the vitamin that we now refer to as “vitamin D.” Scientific investigation of rickets helped establish the role of sunlight in providing us with vitamin D, and it also helped establish the role of vitamin D in bone health.
In the mid1990’s, they found out that it is not only a fat- soluble vitamin, but it is also a hormone. It regulates our metabolism, allowing it to function properly. It helps to regulate our bone development, our muscle function, our immune function, our insulin activity, our calcium balance, and our phosphorus balance. There are receptors for vitamin D, called VDRs, (vitamin D receptors,) on the cell membranes of most cell types in the body, the same as estrogen and cortisol.
Cholesterol is the basic building block of vitamin D in humans. When ultraviolet light hits the cells of our skin, one form of cholesterol found in our skin cells, called 7-dehydrocholesterol, is converted into cholecalciferol, a form of vitamin D3.
But this is not where the vitamin is useful to our bodies. For our bodies to come up with a fully active form of vitamin D3, further metabolism is required.
The first step involves conversion of cholecalciferol into hydroxyvitamin D, also called 25-hydroxyvitamin D or 25(OH)D. Hydroxyvitamin D needs a enzyme called CYP27A1, and is formed in any of the following areas of the body such as the liver, kidneys, lungs, skin, prostate, brain, blood vessel linings, and macrophage cells of the immune system.
The second step involves transforming hydroxyvitamin D into dihydroxyvitamin D. This step needs another enzyme called CYP27B1 and can take place in the lungs, brain, liver, stomach, spleen, kidneys, colon, thymus, lymph nodes, skin, placenta, and in the monocyte and dendritic cells of the immune system.
Ok, after all of that, Dihydroxyvitamin D, which is the only fully active hormonal form of vitamin D, does in actual fact not last for very long in our body. The half-life of this hormone is between 2-3 weeks. For this reason, our vitamin D needs must be met on a fairly regular basis.
And the interesting thing is, we actually need a lot more Vitamin D than we are led to believe.
So what does Vitamin D do?
The hormonal functions of vitamin D include regulation of bone health, muscle health, immune response, insulin and blood sugar, and calcium and phosphorus metabolism.
Lets first look at bone health, with the rising epidemic of osteoporosis, in men as well as women, I think this is one which affects us all.
Our bone is composed of; collagen proteins, keratin proteins, and a variety of minerals including calcium, phosphorus, silicon, boron, and magnesium. But two most critical bone components are calcium and phosphorus. These minerals are the main players in a substance called hydroxyapatite, which accounts for over half of all bone composition.
Hydroxyapatite in bone places a premium on calcium and phosphorus metabolism and their passage in and out of the body. Bone health is regulated by many different substances in the body; growth hormone, testosterone, estrogen, parathyroid hormone (PTH) and vitamin D.
Our parathyroid glands put out PTH whenever our blood calcium levels get too low. PTH then triggers release of calcium from our bones in order to boost our blood level back up to normal. It also triggers our kidneys to retain more calcium for our bloodstream, and excrete more phosphorus to create a more favourable ratio of calcium to phosphorus in our blood. If there is too much PTH released from our parathyroid glands, however, we may end up removing too much calcium from our bones and leaving too much in our blood, compromising both our cardiovascular and our bone health.
Research has shown vitamin D to be associated with healthy parathyroid function. Vitamin D helps the intestines absorb more calcium from our food, and it also helps our kidneys hang on to calcium. But unlike PTH, vitamin D also helps our kidneys retain phosphorus. The two hormones work together in order to assure proper balances of calcium and phosphorus in our bloodstream and in our bones. PTH knows that it must act in partnership with vitamin D because it triggers conversion of hydroxyvitamin D into a hormonally active form dihydroxyvitamin D.
Vitamin D’s role in immune health has reached a point, that whenever researchers are investigating an autoimmune disease, they never do so without considering the possible role of vitamin D. Health conditions like rheumatoid arthritis, multiple sclerosis, Crohn’s disease, systemic lupus erythematosus, are just a few that are affected by vitamin D as well as numerous other autoimmune conditions.
Vitamin D receptors (VDRs) exist on the immune system’s macrophage and dendritic cells. Vitamin D, triggers the macrophage cells to release antibacterial peptides (parts of protein) like cathelicidin, which play a critical role in the immune system’s prevention of infection.
In current research on multiple sclerosis, for example, clinicians are experimenting with vitamin D doses up to 40,000 IU, and in research on rheumatoid arthritis, doses up to 100,000 IU are being used in some clinical trials. (To get some perspective on these vitamin D supplementation levels, they can be compared to the current adult Dietary Reference Intake recommendations for vitamin D, which range from 600 – 2000 IU, unless severely deficient, then up to 5000 IU for only 6 – 12 weeks)
Vitamin D also plays a direct role in regulating our blood pressure by inhibiting the activity of a system called the renin-angiotensin system. It’s the job of the renin-angiotensin system to help increase our blood pressure whenever it gets too low. Optimal levels of vitamin D are needed to hold this system in check, so as to prevent it from raising our blood pressure when not needed, causing us to end up with high blood pressure.
Vitamin D deficiency has been shown to be a significant risk factor for high blood pressure, and risk of high blood pressure during pregnancy.
The key role played by vitamin D in regulation of calcium metabolism has opened the door to research about broader cardiovascular benefits of vitamin D. Overloading of cells with calcium is a problem for heart tissue, and it is associated with increased risk of oxidative stress and tissue damage. By triggering unwanted release of PTH, vitamin D deficiency can result. In several studies, the ability of heart tissue to heal after an event like heart attack has been shown improve significantly when patients have optimal vitamin D levels.
Vitamin D plays an important role in the regulation of insulin metabolism and blood sugar balance. Vitamin D deficiency increases the risk factor for development of type 2 diabetes. Vitamin D levels have been associated with insulin secretion by the beta cells of the pancreas as well as insulin activity once released into the bloodstream.
When vitamin D is deficient in the body and parathyroid hormone (PTH) is released in inappropriately large amounts, too much calcium can accumulate in the cells. When too much calcium accumulates in our fat cells, they end up producing too much cortisol, a hormone that counteracts the effectiveness of insulin. Too much calcium in our fat and muscle cells can inhibit the formation of a protein called GLUT-4. Insulin needs GLUT-4 to help carry sugar (glucose) out of our bloodstream and into our cells. When we lack vitamin D, not enough GLUT-4 is formed, and insulin is unable to this.
Vitamin D has been shown to play a key role in prevention of muscle weakness and prevention of falls, especially in older persons. Vitamin D deficiency has also been associated with too much accumulation of fat throughout muscle tissue, in such a way that muscle strength is decreased and physical performance is compromised. Muscle strength is not related to muscle mass. You can have the same size muscles as someone else, but if you are D deficient, you will not have the same strength.
The role of vitamin D in cancer prevention is a major area of research at present. So far studies have shown a clear role for vitamin D in prevention of the following types of cancer: breast, colon, endometrial, esophageal, ovarian, bladder, gallbladder, gastric, pancreatic, prostate, rectal, and renal cancers, as well as non-Hodgkin’s lymphoma. Indeed, more people die of Vitamin D deficiency-based cancers than from melanoma.
How do you know if you are deficient?
If you have any of the following symptoms you could possibly have vitamin D deficiency.
- Asthma (severe childhood)
- Bones which break easily
- Muscular weakness
- Constant fatigue
- Bladder cancer
- Breast cancer
- Chronic fatigue syndrome
- Colon cancer
- Congestive heart failure
- Crohn’s disease
- Ovarian cancer
- Heart attack
- Inflammatory bowel disease
- Insulin resistance
- Kidney disease
- Liver disease
- Metabolic syndrome
- Multiple sclerosis
- Myofascial pain syndrome
- Periodontal disease
- Rectal cancer
- Rheumatoid arthritis
- Senile dementia
- Type 2 diabetes
- Ulcerative colitis
How do I naturally improve my vitamin D levels?
There are set levels of how much vitamin D you should take daily, but the more I read about using extremely high levels of vitamin D for treatment of diseases, the more I start to feel that we should ingest and absorb as much vitamin D as we possibly can naturally.
I recommend you have a blood test with your doctor to see how low or high your vitamin D levels are before taking on any tablet form of Vitamin D, unless you decide to add Cod liver oil to your diet as part of a health program to up the fish oil factor.
Getting enough UVB sunlight in the range of 290-300nm daily seems perfectly easy, unfortunately this is not so. There is the fluctuating nature of UVB light. UVB rays are needed for skin synthesis of vitamin D, but they are not always present with the same intensity, all day every day. The intensity of UVB light varies dramatically depending on geographical location (latitude), time of year, time of day, degree of cloud cover, and other factors, unlike UVA rays which are present all year round (our aging rays!). Skin pigmentation also plays an important role in skin synthesis of vitamin D. Darker skin pigmentation means less vitamin D synthesis per minute of exposure to UVB light.
Some lifestyles and occupations provide great amounts of sun exposure. Individuals who work outdoors throughout the day in warmer climates have a greater chance of getting good exposure to UVB light and synthesizing adequate amounts of vitamin D. Under optimal circumstances, our skin can synthesize between 10,000-20,000 IU of vitamin D in 30 minutes, again, depending on the angle of the sun, time of day, degree of cloud cover, etc. At the other end of the spectrum, if someone typically wears clothing that blocks a lot of the skin from exposure to sunlight, or is a regular user of sunblock, or works in a job that keeps them indoors throughout the day, chances of adequate vitamin D synthesis are greatly decreased.
The ideal recommended dose of sunshine to receive enough vitamin D is 20 – 40 minutes per day, preferably before 10 am and after 2 pm (11am and 3pm daylight saving).
Since vitamin D is a fat-soluble vitamin, a low fat diet, vegan diet, and/or the presence of certain medical conditions that cause a reduction in the ability to absorb dietary fat may cause vitamin D deficiency. These medical conditions include pancreatic enzyme deficiency, Crohn’s disease, celiac sprue, cystic fibrosis, surgical removal of part or all of the stomach, gall bladder disease, and liver disease.
The most frustrating thing is that the production of vitamin D precursors in the skin, decrease with age. Additionally, with age, the kidneys and many other organ systems and cell types are less able to convert vitamin D into its active hormone form.
What foods provide vitamin D?
Vitamin D is oil soluble, so you need to eat healthy fats to absorb it.
The best food sources for Vitamin D are;
Cod liver oil has been a popular supplement for many years going back to the 1800s when they first found a link to rickets and lack of vitamin D and naturally contains very high levels of vitamin A and vitamin D. Cod liver oil provides 10001IU (1667% DV) per 100 gram serving, or 1360IU (340% DV) in a single tablespoon.
Many types of fish are high in vitamin D. Raw fish contains more vitamin D than cooked, and fatty cuts will contain more than lean cuts. Further, fish canned in oil will have more vitamin D than those canned in water. Raw atlantic herring provides the most vitamin D with 1628IU (271% DV) per 100 gram serving, 2996IU (499% DV) per fillet, and 456IU (76% DV) per ounce. It is followed by pickled herring with 680IU (113% DV) per 100g serving, canned salmon (127% DV), raw mackerel (60% DV), oil packed sardines (45% DV), canned mackerel (42% DV), and oil packed tuna (39% DV).
In addition to vitamin D, oysters are a great source of vitamin B12, zinc, iron, manganese, selenium and copper. Oysters are high in cholesterol and should be eaten in moderation. Raw wild caught eastern oysters provide 320IU (80% DV) per 100 gram serving, 269IU (67% DV) in six medium oysters.
Caviar is a common ingredient in sushi and not as expensive as people think. Caviar provides 232IU (58% DV) of vitamin D per 100 gram serving, or 37.1IU (9% DV) per teaspoon.
Are a good source of Vitamin D, B12 and protein. Eggs provide 37.0IU (9% DV) of vitamin D per 100 gram serving, or 17.0IU (4% DV) in a large fried egg.
More than just a high vitamin D food, mushrooms also provide vitamin B5 (Pantothenic acid) and copper. Lightly cooked white button mushrooms provide the most vitamin D with 27.0IU (7% DV) per 100 gram serving, or 7.6IU (2% DV) per ounce.
Well, I am now off to buy a large platter of sashimi to get my vitamin D up, since I have been sitting at my computer since very early this morning. Not that being sunny would have made any difference, but it would have been nice if the sun were out when I went to hang out the washing, but it was over cast again!