Saturday, July 28, 2007

Fat Soluble Vitamins---Vitamin D---Part II

Let's get back to talking about vitamins, now that my rant is over.

I'm gonna focus on just how to make sure you get enough vitamin D. The best way for you to get vitamin D---Sunlight---Bet you're thinking--hey that's easy---just take a walk outside. You would think so wouldn't you. Let's find out shall we. This is from the Vitamin D Council:

Block the Sun, Block Vitamin D

Remember, our ancestors lived naked in the sun for several million years. Then 50,000 years ago, some of us migrated north and south to places with less sun. Then we put on clothes, started working inside and living in cities where buildings blocked the sun. Then we started traveling in cars instead of walking or riding horses and glass blocked even more of the UVB in the sunlight. Then, only a few years ago, we started actively avoiding the sun and putting on sunblock. All this time we humans have been steadily reducing the tissue levels of the most potent steroid hormone in our bodies, one with powerful anti-cancer properties.

The really significant reductions in sunlight exposure have occurred since the industrial revolution, just the time the "diseases of civilization," like cardiovascular disease, diabetes and cancer, seem to have greatly increased. Pretty frightening when you think about it.

Then we have this from the Linus Pauling Institute:

Sunlight exposure provides most people with their entire vitamin D requirement. Children and young adults who spend a short time outside two or three times a week will generally synthesize all the vitamin D they need. The elderly have diminished capacity to synthesize vitamin D from sunlight exposure and frequently use sunscreen or protective clothing in order to prevent skin cancer and sun damage. The application of sunscreen with an SPF factor of 8 reduces production of vitamin D by 95%. In latitudes around 40 degrees north or 40 degrees south (Boston is 42 degrees north), there is insufficient UVB radiation available for vitamin D synthesis from November to early March. Ten degrees farther north or south (Edmonton, Canada) this “vitamin D winter” extends from mid October to mid March. According to Dr. Michael Holick, as little as 5-10 minutes of sun exposure on arms and legs or face and arms three times weekly between 11:00 am and 2:00 pm during the spring, summer, and fall at 42 degrees latitude should provide a light-skinned individual with adequate vitamin D and allow for storage of any excess for use during the winter with minimal risk of skin damage.
My point here is sunlight is good for you--but you have to be EXPOSED to the UVB to do any good. How many of y'all out there wear sunscreen? Well I do. Simply because many of the psych meds I take make you photosensitive.
So that means I'm not being exposed to the UVB as I should be. Which in turn means I'm not making enough Vitamin D. Which then means I need a supplement. But having had WLS, I don't absorb Vitamin D very well. Sheesh, my head is spinning just from typing all that. So now what am I suppose to do?

You can get Vitamin D from the food you eat.

Vitamin D is found naturally in very few foods. Foods containing vitamin D include some fatty fish (mackerel, salmon, sardines), fish liver oils, and eggs from hens that have been fed vitamin D. In the U.S., milk and infant formula are fortified with vitamin D so that they contain 400 IU (10 mcg) per quart. However, other dairy products such as cheese and yogurt are not always fortified with vitamin D. Some cereals and breads are also fortified with vitamin D. Recently, orange juice fortified with vitamin D has been made available in the U.S. Accurate estimates of average dietary intakes of vitamin D are difficult because of the high variability of the vitamin D content of fortified foods. Vitamin D contents of some vitamin D-rich foods are listed in the table below in both international units (IU) and micrograms (mcg). For more information on the nutrient content of foods you eat frequently, search the USDA food composition database.

Food Serving Vitamin D (IU) Vitamin D (mcg)
Pink salmon, canned 3 ounces 530 13.3
Sardines, canned 3 ounces 231 5.8
Mackerel, canned 3 ounces 214 5.4
Quaker Nutrition for Women Instant Oatmeal 1 packet 140 3.5
Cow's milk, fortified with vitamin D 8 ounces 100 2.5
Orange juice, fortified with vitamin D 8 ounces 100 2.5
Cereal, fortified 1 serving (usually 1 cup) 40-50 1.0-1.3
Egg yolk 1 medium 25 0.63

Y'all already know I live a low carb life so I recommend the fish, fish oils or eggs. You don't need all that fortified food---in my opinion. But there is no way to get all the Vitamin D you need just from food. Dr Davis from the HeartScan blog has this to say.

You'll note that the only naturally-occurring food sources of vitamin D are the modest quantities in fish, egg yolks, and liver. All the other vitamin D-containing foods like cereal, milk, and other dairy products have vitamin D only because humans add it.

It takes me (personally) 6000 units of vitamin D per day to bring my blood level to an acceptable 50 ng/ml. To obtain this from eating salmon, I would have to eat 58 ounces, or 3 1/2 pounds of salmon--every day. Or, I could eat 30 cans of tuna fish.

If I didn't want to eat loads of fish every day, I could drink 60 glasses of milk every day. After I recovered from the diarrhea, my vitamin D might be adequate, provided the milk indeed contained the amount stated on the label (which it often does not when scrutinized by the USDA).
If vitamin D is a vitamin, how are humans supposed to get sufficient quantities? I don't know anybody who can eat 3 1/2 lbs of salmon per day, nor drink 60 glasses of milk per day. But aren't vitamins supposed to come from food?

The problem is that vitamin D is not really a vitamin, it's a hormone. If your thyroid hormone level was low, you'd gain 20, 30, or more pounds in weight, your blood pressure would skyrocket, you'd lose your hair, become constipated, develop blood clots, be terribly fatigued. In other words, you'd suffer profound changes. Likewise, if thyroid hormone levels are corrected by giving you thyroid hormone, you'd experience profound correction of these phenomena.

That's what I'm seeing with vitamin D: restoration of this hormone to normal blood levels (25-OH-vitamin D3 50 ng/ml) yields profound changes in the body.
There are many risk factors that contribute to Vitamin D deficiency. Having WLS is just one of them.
  • Exclusively breast fed infants: Infants who are exclusively breast fed and do not receive vitamin D supplementation are at high risk of vitamin D deficiency, particularly if they have dark skin and/or receive little sun exposure. Human milk generally provides 25 IU of vitamin D per liter, which is not enough for an infant if it is the sole source of vitamin D. Older infants and toddlers exclusively fed milk substitutes and weaning foods that are not vitamin D fortified are also at risk of vitamin D deficiency. The American Academy of Pediatrics recommends that all infants that are not consuming at least 500 ml (16 ounces) of vitamin D fortified formula or milk be given a vitamin D supplement of 200 IU/day.
  • Dark skin: People with dark skin synthesize less vitamin D on exposure to sunlight than those with light skin. The risk of vitamin D deficiency is particularly high in dark-skinned people who live far from the equator. In the U.S., 42% of African American women between 15 and 49 years of age were vitamin D deficient compared to 4% of White women.
  • Aging: The elderly have reduced capacity to synthesize vitamin D in the skin when exposed to UVB radiation, and are more likely to stay indoors or use sunscreen. Institutionalized adults are at extremely high risk of vitamin D deficiency without supplementation.
  • Covering all exposed skin or using sunscreen whenever outside: Osteomalacia has been documented in women who cover all of their skin whenever they are outside for religious or cultural reasons. The application of sunscreen with an SPF factor of 8 reduces production of vitamin D by 95% .
  • Fat malabsorption syndromes: Cystic fibrosis and cholestatic liver disease impair the absorption of dietary vitamin D. (add WLS here)
  • Inflammatory bowel disease: People with inflammatory bowel disease like Crohn’s disease appear to be at increased risk of vitamin D deficiency, especially those who have had small bowel resections.
  • Obesity: Obesity increases the risk of vitamin D deficiency. Once vitamin D is synthesized in the skin or ingested, it is deposited in body fat stores, making it less bioavailable to people with large stores of body fat.

So how do you know when you are taking enough. Vitamin D can go both ways. It can be bad if you get too little or too much. According to research Vitamin D toxicity is extremely rare, but deficiency is very common.

Growing awareness that vitamin D insufficiency has serious health consequences beyond rickets and osteomalacia highlights the need for accurate assessment of vitamin D nutritional status. Although there is general agreement that the serum 25(OH)D level is the best indicator of vitamin D deficiency and sufficiency, the cutoff values have not been clearly defined. While laboratory reference ranges for serum 25(OH)D levels are often based on average values from populations of healthy individuals, recent research suggests that health-based cutoff values aimed at preventing secondary hyperparathyroidism and bone loss should be considerably higher. In general, serum 25(OH)D values less than 20-25 nmol/L indicate severe deficiency associated with rickets and osteomalacia. Although 50 nmol/L has been suggested as the low end of the normal range, more recent research suggests that PTH levels and calcium absorption are not optimized until serum 25(OH)D levels reach approximately 80 nmol/L . Thus, at least one vitamin D expert has argued that serum 25(OH)D values less than 80 nmol/L should be considered deficient, while another suggests that a healthy serum 25(OH)D value is between 75 nmol/L and 125 nmol/L. Data from supplementation studies indicates that vitamin D intakes of at least 800-1,000 IU/day are required by adults living in temperate latitudes to achieve serum 25(OH)D levels of at least 80 nmol/L.
Vitamin D plays a major role in disease prevention. Which to me is the most important role of all. You can ward off so many things like Osteoporosis, Cancer of many types (Colorectal Cancer, Breast Cancer, Prostate Cancer), Autoimmune Diseases, and Hypertension (High Blood Pressure). It also plays a major role in the brain--which I will discuss in a future post.

I'd also like to stress that when taking a Vitamin D supplement, you must look at what kind it is. D3 (cholecalciferol) is the preferred form. Vitamin D found in multivitamins and calcium/vitamin D combinations is D2(ergocalciferol) and useless. It is also more associated with Vitamin D toxicity. But as I pointed out in the Part I of this series, Vitamin D must be taken in an oiled base formula NOT pills.

In closing, I want to again stress the importance of being proactive in your own health care. That goes for anyone. Most docs do not know or they just fail to do these essential blood levels.