Vitamin D and Breast Cancer

Source: Breast Investigators

Is Your Vitamin D Level Putting You at Risk?

Published by: Angela Long on 30th Mar 2010

Vitamin D Facts

Source: Vitamin D Council

Understanding Vitamin D Cholecalciferol

The high rate of natural production of vitamin D3 cholecalciferol (pronounced koh·luh·kal·sif·uh·rawl) in the skin is the single most important fact every person should know about vitamin D—a fact that has profound implications for the natural human condition.

Technically not a "vitamin," vitamin D is in a class by itself. Its metabolic product, calcitriol, is actually a secosteroid hormone that targets over 2000 genes (about 10% of the human genome) in the human body. Current research has implicated vitamin D deficiency as a major factor in the pathology of at least 17 varieties of cancer as well as heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects, periodontal disease, and more.

Vitamin D's influence on key biological functions vital to one's health and well-being mandates that vitamin D no longer be ignored by the health care industry nor by individuals striving to achieve and maintain a greater state of health.

Sunshine and Your Health

If well adults and adolescents regularly avoid sunlight exposure, research indicates a necessity to supplement with at least 5,000 units (IU) of vitamin D daily. To obtain this amount from milk one would need to consume 50 glasses. With a multivitamin more than 10 tablets would be necessary. Neither is advisable.

The skin produces approximately 10,000 IU vitamin D in response 20–30 minutes summer sun exposure—50 times more than the US government's recommendation of 200 IU per day!

How To Get Enough Vitamin D

There are 3 ways for adults to insure adequate levels of vitamin D:

  • regularly receive midday sun exposure in the late spring, summer, and early fall, exposing as much of the skin as possible (being careful to never burn).
  • regularly use a sun bed (avoiding sunburn) during the colder months.
  • take 5,000 IU per day for 2–3 months, then obtain a 25-hydroxyvitamin D test. Adjust your dosage so that blood levels are between 50–80 ng/mL (or 125–200 nM/L) year-round.

Vitamin D's Co-factors

Vitamin D has co-factors that the body needs in order to utilize vitamin D properly. They are:

  • magnesium
  • zinc
  • vitamin K2
  • boron
  • genestein
  • a tiny amount of vitamin A

Magnesium is the most important of these co-factors. In fact, it is common for rising vitamin D levels to exacerbate any underlying magnesium deficiency. If one is having problems supplementing with vitamin D, a magnesium deficiency could be the reason why.

Read more about vitamin D's co-factors!
 

Vitamin D Foods

Source:  Office of Dietary Supplements - National Institute of Health

 

Sources of Vitamin D

Food
Very few foods in nature contain vitamin D. The flesh of fish (such as salmon, tuna, and mackerel) and fish liver oils are among the best sources [4]. Small amounts of vitamin D are found in beef liver, cheese, and egg yolks. Vitamin D in these foods is primarily in the form of vitamin D3 (cholecalciferol) and its metabolite 25(OH)D3 [23]. Some mushrooms provide vitamin D2 (ergocalciferol) in variable amounts [24-26]. Mushrooms with enhanced levels of vitamin D2 from being exposed to ultraviolet light under controlled conditions are also available.

Fortified foods provide most of the vitamin D in the American diet [4,26]. For example, almost all of the U.S. milk supply is fortified with 100 IU/cup of vitamin D (25% of the Daily Value or 50% of the AI level for ages 14-50 years). In the 1930s, a milk fortification program was implemented in the United States to combat rickets, then a major public health problem. This program virtually eliminated the disorder at that time [4,14]. Other dairy products made from milk, such as cheese and ice cream, are generally not fortified. Ready-to-eat breakfast cereals often contain added vitamin D, as do some brands of orange juice, yogurt, and margarine. In the United States, foods allowed to be fortified with vitamin D include cereal flours and related products, milk and products made from milk, and calcium-fortified fruit juices and drinks [27]. Maximum levels of added vitamin D are specified by law.

Several food sources of vitamin D are listed in Table 3.

Table 3: Selected Food Sources of Vitamin D [30]

 

Food

IUs per serving*

Percent DV**

Cod liver oil, 1 tablespoon

1,360

340

Salmon (sockeye), cooked, 3 ounces

794

199

Mushrooms that have been exposed to ultraviolet light to increase vitamin D, 3 ounces (not yet commonly available)

400

100

Mackerel, cooked, 3 ounces

388

97

Tuna fish, canned in water, drained, 3 ounces

154

39

Milk, nonfat, reduced fat, and whole, vitamin D-fortified, 1 cup

115-124

29-31

Orange juice fortified with vitamin D, 1 cup (check product labels, as amount of added vitamin D varies)

100

25

Yogurt, fortified with 20% of the DV for vitamin D, 6 ounces (more heavily fortified yogurts provide more of the DV)

80

20

Margarine, fortified, 1 tablespoon

60

15

Sardines, canned in oil, drained, 2 sardines

46

12

Liver, beef, cooked, 3.5 ounces

46

12

Ready-to-eat cereal, fortified with 10% of the DV for vitamin D, 0.75-1 cup (more heavily fortified cereals might provide more of the DV)

40

10

Egg, 1 whole (vitamin D is found in yolk)

25

6

Cheese, Swiss, 1 ounce

6

2

*IUs = International Units.

**DV = Daily Value. DVs were developed by the U.S. Food and Drug Administration to help consumers compare the nutrient contents of products within the context of a total diet. The DV for vitamin D is 400 IU for adults and children age 4 and older. Food labels, however, are not required to list vitamin D content unless a food has been fortified with this nutrient. Foods providing 20% or more of the DV are considered to be high sources of a nutrient.

The U.S. Department of Agriculture's Nutrient Database Web site, http://www.nal.usda.gov/fnic/foodcomp/search, lists the nutrient content of many foods and provides a list of foods containing vitamin D: http://www.ars.usda.gov/SP2UserFiles/Place/12354500/Data/SR22/nutrlist/sr22a324.pdf. A growing number of foods are being analyzed for vitamin D content. Simpler and faster methods to measure vitamin D in foods are needed, as are food standard reference materials with certified values for vitamin D to ensure accurate measurements [31].