Vitamin D
Updated: 17 hours ago
More and more doctors are testing levels of Vitamin D 25-Hydroxy as a regular part of their patient maintenance and prescribing it when levels are low. The question is what is the optimum level of vitamin D for a cancer patient?
An article published online in the European Journal of Cancer reports the results of two meta-analyses conducted by researchers at the German Cancer Research Center in Heidelberg, which affirm a protective effect for higher levels of vitamin D against the risk of dying from breast cancer as well as colorectal cancer.
The researchers selected five studies that involved 4,413 breast cancer patients and five studies that included 2,330 colorectal cancer patients, Analysis of the selected studies uncovered a 38% average lower risk of dying from any cause and a 42% lower risk of dying from breast cancer when the highest versus lowest categories of serum 25-hydroxyvitamin D levels were compared. For colorectal cancer, the risk averaged 29% lower for all-cause mortality and 35% lower for disease-specific death among the highest groups.
Editor's Note:Authors Hiafa Maalmi and colleagues note, "The rather consistent results found in our met-analyses suggest vitamin D supplementation might bear a potential to improve prognosis among colorectal and breast cancer patients, as suggestion that should be followed up and tested in randomized controlled trials."
(Life Extention July 2014)
(This article is mostly taken from the February 2007 issue of the Harvard Men's Health Watch.)
Vitamin D is one of the 13 vitamins discovered in the early 20th century by doctors studying nutritional deficiency diseases The search finally identifed this nutrient as a cure for rickets, a painful childhood bone disease. Within a decade, the fortification of foods with vitamin D was under way, and rickets became rare in the United States. But solving the problem of rickets was only the beginning of research into vitamin D. Results suggest that vitamin D may have an important role in many aspects of human health, from bone fractures to prostate cancer, cardiovascular disease, neuromuscular problems, and diabetes.
Ever since those early days, scientists have defined vitamins as organic (carbon-containing) chemicals that must be obtained from dietary sources because they are not produced by the body’s tissues. Vitamins play a crucial role in our body’s metabolism, but only tiny amounts are needed to fill that role.
Although vitamin D is firmly enshrined as one of the four fat-soluble vitamins, it is not technically a vitamin. True, it’s essential for health, and only minuscule amounts are required. But it breaks the other rules for vitamins because it’s produced in the human body, it’s absent from all natural foods except fish and egg yolks, and even when it’s obtained from foods, it must be transformed by the body before it can do any good.
Vitamin D is not one chemical but many. The natural type is produced in the skin from a universally present form of cholesterol, (here's where you need that pesky cholesterol again!) 7-dehydrocholesterol. Sunlight is the key: Its ultraviolet B (UVB) energy converts the precursor to vitamin D3. In contrast, most dietary supplements are manufactured by exposing a plant sterol to ultraviolet energy, thus producing vitamin D2. Because their function is almost identical, D2 and D3 are lumped together under the name vitamin D — but neither will function until the body works its magic (see figure).
How your body makes vitamin D
The sun’s energy turns a chemical in your skin into vitamin D3, which is carried to your liver and then your kidneys to transform it to active vitamin D.
The first stop is in the liver, where vitamin D picks up extra oxygen and hydrogen molecules to become 25-hydroxyvitamin D, or 25(OH)D. This is the chemical that doctors should measure to diagnose vitamin D deficiencies. But although 25(OH)D is used for diagnosis, it can’t function until it travels to the kidney. There it acquires a final pair of oxygen and hydrogen molecules to become 1,25 dihydroxyvitamin D; scientists know this active form of the vitamin as 1,25(OH)2D, or calcitriol, but for ordinary folks the name vitamin D is accurate enough.
How to successfully metabolize Vitamin D
Take Vitamin D With Your Heaviest Meal. Vitamin D is a fat-soluble nutrient, so it's important to take it with the largest meal of the day.
A Cleveland Clinic Foundation study showed that when people take vitamin D with the largest meal of the day, blood levels increase over 50% compared to taking vitamin D on an empty stomach or with a light meal.
It is thus critical to not only take enough vitamin D, but to also take it with the meal that contains the most fat to ensure maximum absorption.
When you hear negative stories claiming that vitamins don't work, a closer examination reveals the dose is too low and instructions as to when to take the nutrient, such as with the heaviest meal of the day, are not given.
Insufficient vitamin D is linked to virtually every age-related disorder including cancer, vascular disease, and chronic inflammation.
Human studies show that higher levels of vitamin D protect against cancer and other age-related ailments.
As humans age, they lose the ability to convert sunlight to vitamin D in their bodies.
Scientists have identified reduced vitamin D levels in winter months as a prime suspect for the seasonal increase in infectious disease cases.
Aging persons need to supplement with about 5,000 IU of vitamin D each day and have regular blood tests to achieve optimal blood levels.
Individuals with certain chronic health conditions may not be able to take higher doses of vitamin D.
Ideal ranges for 25-hydroxyvitamin D are between 50-80 ng/mL. It took me a while to find out where the 80ng/mL number that is recommended came from. They tested young healthy and unsupplemented lifeguards at the end of the summer who spent the whole season out in the sun. They're blood levels averaged 80mg/mL.
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