Breast Density, Vitamin D3 and Growth Factors

The hormone Insulin-like growth factor-1 is a known growth factor for normal and malignant breast cells.

http://www.ncbi.nlm.nih.gov/entrez/queryd.fcgi?cmd=Retrieve&db=pubmed&
dopt=Abstract&list_uids=16187236&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/queryd.fcgi?cmd=Retrieve&db=pubmed&
dopt=Abstract&list_uids=11559546&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/queryd.fcgi?cmd=Retrieve&db=pubmed&
dopt=Abstract&list_uids=11704861&itool=pubmed_docsum

Breast density refers to an increase in cell mass within the breast. Women with increased breast cell densities have up to a 6 fold increased risk of developing breast cancer.

http://www.ncbi.nlm.nih.gov/entrez/queryd.fcgi?cmd=Retrieve&db=pubmed&
dopt=Abstract&list_uids=15066922&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/queryd.fcgi?cmd=Retrieve&db=pubmed&
dopt=Abstract&list_uids=10919644&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/queryd.fcgi?cmd=Retrieve&db=pubmed&
dopt=Abstract&list_uids=15894654&itool=pubmed_docsum

IGF-1 is the actual growth factor for a variety of cell types in the breast and other tissues. IGFBP3, or IGF-1 binding protein 3, is an INHIBITOR of IGF-1 activity. Therefore, increased breast cell density is associated with increased levels of IGF-1 and decreased levels of IGFBP3.

In the previous Blog, I discussed how vitamin D3 inhibited the development of pre-cancer lesions in the breast. Now we know how.

Vitamin D3 and calcium reduce breast cell density. In this study of human volunteers, a small dose of 400IU of vitamin D3 and 1 gram of calcium a day reduced breast cell density by 8.5%, as indicated by mammogram. This is remarkable. 400 IU of vitamin D3 is nothing when you consider that 25,000 IU of vitamin D3 can be made in the skin by a slight sunburn.

http://www.ncbi.nlm.nih.gov/entrez/queryd.fcgi?cmd=Retrieve&db=pubmed&
dopt=Abstract&list_uids=16030097&itool=pubmed_docsum

The following study shows that vitamin D3 and calcium reduce breast cell density PRIMARILY in women with elevated levels of IGF-1 in their system. This data obvious suggests that vitamin D3 and calcium INHIBIT IGF-1 synthesis or activity, thereby decreasing breast cell density and reducing the risk of breast cancer.

http://www.ncbi.nlm.nih.gov/entrez/queryd.fcgi?cmd=Retrieve&db=pubmed&
dopt=Abstract&list_uids=16397276&itool=pubmed_docsum

Vitamin D3 inhibits IGF-1 signaling in breast cancer cells and causes their death.

http://www.ncbi.nlm.nih.gov/entrez/queryd.fcgi?cmd=Retrieve&db=pubmed&
dopt=Abstract&list_uids=10674019&itool=pubmed_docsum

The conclusion that can be safely drawn is that vitamin D3, made primarily in skin by exposure to sunshine, can BOTH prevent the development of breast cancer and promote the death of established breast cancer cells.

We will discuss genetic factors that predispose to breast cancer in the next Blog. However, for most women, simple exposure to ultraviolet B sunlight or vitamin D3 supplements plus calcium can go a VERY LONG way toward preventing breast cancer.

And that ain't bad!!!

Not everything in life has to be complicated.

Stay tuned...

Grouppe Kurosawa, Medicine in the Public Interest
(http://www.grouppekurosawa.com)