THE IMPORTANCE OF VITAMIN D
I felt this would be a good time to talk about something most Oregonians crave this time of year, the sun! Most doctors advise their patients to stay out of the sun or wear sunscreen at all times. Skin cancer is definitely on the rise (it accounts for half of all cancers today) and is the primary factor in sun exposure phobia. Unfortunately one of our most important vitamins is manufactured in the skin with sun exposure.
Vitamin D was discovered in the mid-1800's when people noticed that cod-liver oil cured and prevented rickets (a bone disease in Vit. D deficient children). They felt it had to be some vitamin that provided this benefit. At that time Vitamin A, B, and C had been identified so they called this Vit. D. Some say Vit. D is more of a hormone than a vitamin. It is somewhat complicated in that in its initial form as a food it is non-active in the body. It has to travel to the liver where it is modified and then to the kidneys where an active form of the vitamin (125-dihydroxy) is made. If a person is suffering from liver or kidney disease, this process gets disrupted. (These cases require a prescription form of active Vit. D)
Its main function is facilitating absorption and regulation of calcium in the body. It has an equally important job in the regulation of cell growth. (I will talk more about this in a minute.) The primary dietary source of Vit. D is found in fatty fish but small amounts are also found in fortified milk and cereal. The best source of Vit. D though is from direct exposure to the sun. Our skin has the ability to make massive amounts of Vit. D with just a few minutes of direct sun exposure. Unfortunately, sunscreen of SPF 8 or stronger blocks this process and here lies the problem. People who live in northern latitudes get very little sun in the winter months and when the sun does come out, their extreme fears of skin cancer brings out the sunscreen before they ever step outside.
A recent study done in Boston looking at young adults age 18 to 29 found 32% were Vit. D deficient by the end of the winter. Another study done in Maine looked at Caucasian girls ages 9-11 that found 48% were Vit. D deficient by the end of the winter and 17% of those remained deficient by the end of the summer due to use of sunscreen. The elderly, who are more likely to be indoors, have skin that is less efficient at making Vit. D, and kidneys that are less efficient at making the active form of it, are on average 50-60% Vit. D deficient. African-Americans and Hispanic are also more prone to this problem due to the increased pigment in their skin. They often need two or three times the sun exposure that fair skin populations do to make the same amount of Vit. D. Another study done at a Boston hospital looked at the blood levels of active Vit. D in 50 pregnant women (mostly African-American and Hispanic) coming in for delivery. 76% were found to be extremely Vit. D deficient and 81% of their new born babies were severely deficient. Breastfeeding continues the infant's deficiency due to the mother's deficiency.
Other risk factors are:
--People who are on consistent steroid medication which is thought to reduce the metabolism of Vit. D. (A study done where kidney transplant patients were given Vit. D and Calcium along with the standard steroid medication had significantly less bone loss than what is normally seen in post transplant surgeries.)
--People with fat mal-absorption syndromes such as: Crohn's disease, Celiac disease, Liver disease, Cystic Fibrosis, Chronic Colitis or IBS, and Pancreatic enzyme deficiencies.
COMPLICATIONS OF VIT. D DEFICIENCY
One of the most common problems is osteoporosis. Your body absorbs only about 30% of the calcium you consume even with optimal Vit. D. If you are deficient in D, you will only absorb about 10%. Another and more devastating disease is called Osteomalacia and is known as the adult form of rickets. It ultimately leads to soft bones but can cause severe pain in the bone as well as the muscle and is often mis-diagnosed as Fibromyalgia. Being a Chiropractor, I find patients have less chronic muscle/joint pain when the weather is warm and the sun is out; could vitamin D be part of this?
Cancer is another big concern due to Vit. D's ability to control cell growth. Studies published in the US and Europe have shown that optimal levels of Vit. D can reduce the risk of colon, breast, and prostate cancer by 50%. Ironically, it is also thought to inhibit the development of the more fatal skin cancer, malignant melanoma. When researchers look at cancer rates in general, the numbers increase as the latitude increases; as a rule, populations in the north have greater numbers of cancer and decreased rates of survival.
Seasonal Affective Disorder is another area researchers have been looking at where one study found increasing the 125-dihydroxy levels (the active form of Vit. D) made significant improvement suggesting a Vit. D link to this disorder. Vitamin D is also being used to treat Psoriasis due to its ability to control cell growth.
HOW MUCH VIT. D DO WE NEED?
New research has drastically changed many opinions on what is an adequate dose of Vit. D. If you test very low on a blood screen, take 10,000 IU/day for 6 weeks. If you don't know or are normal, I would recommend 4000 IU/day during the winter months, or year round if you avoid the sun in the summer. I would highly recommend getting your Vit. D from the sun when possible. As far as sun exposure; a Caucasian would only need to expose 10% of his/her body for 10-15 minutes, 2-3x/week. That doesn't sound like much but if you go most of the year without getting any sun; it is very easy for your body to become deficient. If you are deficient, it takes more to build your body back up. Dr. Holick treats patients with vitamin D deficiency with 50,000 IUs once/wk for 8 weeks.
So, if you feel compelled to grab that sunscreen; wait for 10-15 minutes of sun before you put it on to get that very important Vit. D. Your body regulates this process so it is not possible to get too much Vit. D from the sun. In fact, if you get regular sun in the spring, summer, and fall, your body will store enough in the tissue to get you through 3 months of winter but I often recommend taking cod-liver oil for a great source of vitamin D in winter months. (and yes you can get it in capsules; I recommend Nordic Naturals or Carlson's) There is also a blood test that can measure your levels of active Vit. D if you feel you may be deficient.
DOES SUN EXPOSURE REALLY INCREASE CANCER RISK?
You can get many different opinions on this subject but some of the latest research says that small amounts of sun are very healthful for you. There are two types of skin cancer, basal cell carcinoma, and malignant melanoma. Basal Cell (or squamous cell) carcinoma is easily treatable and rarely serious while malignant melanoma can be very aggressive and often fatal. Sun screens are accepted as a good prevention for carcinomas but recent research from Memorial Sloan-Kettering Cancer Center in New York indicates that sunscreens do not prevent the more deadly melanoma cancers. They went on to state that sunscreen allows fair skin people to remain in the sun much longer which may be a risk factor for this cancer. In other words, you can not depend on sunscreen to protect you from malignant melanoma. They list genetics, as well as being fair skinned and having an increased number of moles, as a risk factor for melanoma. The best advice for those at risk is to use clothing for protection whenever possible.
Another controversy getting more attention recently is: are sunscreens really safe to use? The main chemical and active ingredient in sunscreen is Octyl methoxycinnamate (OMC). A recent study from Norway using very small doses of this chemical (compared to the dose you get in sunscreen) on mice cell cultures found a 50% cell death rate compared to a control model. When these cells were exposed to UV light to simulate mid- day sun, the toxic effect doubled. Some also feel that these chemicals become more toxic when they come in contact with Chlorine (such as used in swimming pools). No one can say that human tissue reacts the same as in animal studies but Terje Christensen, a biophysicist from the Norwegian Radiation Protection Authority said her research showed that sunscreens should be treated with caution and only used when it is impractical to use clothing for protection. In addition to OMC, many sunscreens contain Titanium dioxide which the National Institute for Occupational Safety and Health have labeled "a potential occupational carcinogen". Researchers have recently stated that this chemical can penetrate human skin. Another theory that has some research behind it is the increasing number of skin cancer cases are due to our extreme fatty acid imbalance between Omega-6 oils and Omega-3's. It is thought that this imbalance makes the skin more vulnerable to UV damage. As most of you know I am a strong advocate for taking fish oil so this just added one more good reason for me.
I think the bottom line, take home lesson is like most things in life: moderation! Get a little bit of sun on a regular basis but try to avoid direct exposure to the mid-day sun. Try to use clothing to protect you whenever possible and sunscreen in moderation. Last but not least, if you are not taking fish oil, you should be! On that note, I wanted to let all of you know that I am selling Nordic Natural Fish Oil (known as one of the best pharmaceutical grade fish oils available). I offer it at a substantial reduction over what retail stores sell it for if any of you are interested. I have two formulas: ProOmega, 120 count with: 650 mg of EPA. 450mg of DHA and 180 mg of other Omega 3 fatty acids for $40. The other formula is called ProEPA, 120 count with 850 mg of EPA, 200 mg of DHA and 180 of other Omega 3s for $38. Retail on both of these is $48. I would be happy to ship to you for the cost of postage. Both of these are a 2 month supply for one person. If you are someone who suffers from inflammation or vascular/heart problems, I would recommend the ProEPA.
Hope you have a great summer! Soak up a little sun and get those vitamin D levels up for the coming winter clouds.
Yours in Health,
Dr. Roy Murrell, DC 200 NE 20th Avenue, Suite 140 Portland Oregon 97232 - disclaimer - 971-312-9497