Scientists at the University of Alabama recently published a seminal article on the use of botanicals for the prevention of skin cancer induced by ultraviolet sunlight. As discussed in less technical language in our lead article, the key finding was that a compound in grape seed extract inhibits UVB-induced immune suppression. To see the article describing this research, click here. "Dietary grape-seed proanthocyanidin inhibition of ultraviolet B-induced immune suppression is associated with induction of IL-12" Carcinogenesis 2006 27(1):95-102. This Research Update column highlights articles related to recent scientific inquiry into the process of human aging. It is not intended to promote any specific ingredient, regimen, or use and should not be construed as evidence of the safety, effectiveness, or intended uses of the Juvenon product. The Juvenon label should be consulted for intended uses and appropriate directions for use of the product.

By Benjamin V. Treadwell, Ph.D.

“Eat your fruits and vegetables,” we are told by our mother and also by most nutritionists, as well as a few physicians. But why, especially if we don’t like them?

Epidemiological studies have compared populations that consume significant amounts of fruits, vegetables and beans (legumes) to those that have little plant food in their diet. People on the former diet are much healthier overall.

Just what is present in plants that we seem to require for maximum health?

Research indicates that many important compounds contained in plants may have health-promoting benefits. The table below shows a few examples.

Plant	Active Compound	Health Benefits
Broccoli (broccoli sprouts)	sulforaphane	Cancer, blood pressure, potent inducer of antioxidants
Grapes (grape seed, skin)	proanthocyanidins, resveratrol	Cancer of skin, blood pressure, cardiovascular health, possibly increased life span
Turmeric	curcumin	Anti-inflammatory, cancer, Alzheimer’s disease, arthritis
Tomato paste	lycopene	Breast, prostate and other cancers
Green tea, cocoa	catechins	Cancer, cardiovascular health, blood pressure, weight control

One of the most obvious health-promoting components of plant food, not cited in the table, is the vitamin content. Vitamin deficiency is perhaps the most common cause of many disease states, including cancer, dysfunction of the nervous system, cardiovascular system, and overall physical and mental health. However, that topic is for a future health letter.

		Some Questions Persons with certain auto-immune diseases, such as multiple sclerosis, have an imbalance in the ratio of IL-10/IL-12 in favor of IL-12. Multiple sclerosis is most prevalent among populations living in areas with limited sun exposure. Is it possible that persons with this condition would benefit from sun exposure? On the flip side, do MS patients have a lower incidence of sun-induced skin cancer?

To illustrate how compounds from plants can protect our health, today's journal will focus on a group of compounds, the proanthocyanidins, present in a number of plant foods and particularly concentrated in an extract made from grape seeds. Although recent research indicates these compounds have numerous health-promoting properties, the focus of this report will be on their potential in protecting our skin from age-associated wrinkles, fragile skin, and more importantly, skin cancer.

What are proanthocyanidins?

The proanthocyanidins are large molecules synthesized by certain plants, including grapes, where they are concentrated in the seeds. They function as a defense system to protect the plant from predators, as well as damage from the sun. They are similar in structure to other compounds, called catechins, present in cocoa and tea, that contain chemical groups capable of functioning as antioxidants. In fact, the proanthocyanidins are really polymerized catechins that form a much larger phenolic structure.

How does the sun damage our skin and promote cancer?

Ultraviolet rays from the sun, especially extended exposure to ultraviolet-B (UVB) rays, can have deleterious effects on the skin and capillaries. The damage is exhibited as wrinkled and easily bruised skin due to damaged and weakened capillaries, and skin cancer. These effects become more evident as we age, since the damage is cumulative. UVB induced damage appears to at least partially involve damage to the immune system. It is known that this energetic light can promote the production of oxidants — free radicals — in the exposed tissues. The skin does have a built-in defense system comprised of anti-oxidant enzymes, as well as oxidant-protective molecules such as vitamins E and C. However, with time and/or intense exposure, the defense system becomes overwhelmed, and the free-radicals attack the tissue constituents, such as collagen, membrane components, and the genetic material DNA. The consequence is wrinkled and fragile skin as well as a significant chance of one or more of the cells of the skin turning cancerous as a result of altered DNA. Furthermore, the immune system of the skin, which recognizes and destroys abnormal precancerous cells, is compromised as it too is damaged by the ultraviolet rays.

How does grape seed extract protect the skin from UV-B?

Grape seed extract contains proanthocyanidins. Scientists have now demonstrated the protective effects of proanthocyanidins in a mouse model of UVB-induced photocarcinogenesis. Mice fed a diet containing these compounds had a decreased incidence of skin cancer compared to controls. As mentioned above, the immune system is a key player in protection from skin cancer. It turns out that specific cells of the immune system, the thymocytes, over-produce an immunosuppressant protein IL-10, and under-produce a stimulant of the immune system, IL-12, after excess UVB exposure. Additional research demonstrates that the imbalance of these important components of the immune system is the probable cause of a UVB damaged skin cell progressing to a cancerous state. In other words, UVB suppresses the immune system, and a diet containing proanthocyanidins significantly attenuates this suppressive effect. The probable mechanism for this protection is the potent capacity of these compounds to combine with and neutralize the UVB-induced free radicals before they react with and damage cells, including the immune cells of the skin.