Current knowledge of grape seed extract emerged from research conducted at French medical centres, notably at the University of Bordeaux. Throughout most of Europe, and especially in France, moderate consumption of red wine is a cultural tradition. In recent years, both red wine and, interestingly, grape seeds, have been found to have definite health-promoting properties. Now its many benefits are available in a convenient standardised form, as grape seed extract.
Grapes are native to Asia near the Caspian Sea, and were later brought to North America and Europe. This plant’s climbing vine has large, jagged leaves and the grapes may be green, red, or purple. The seed extract is derived from the seeds found within the grapes themselves.
Grape seed contains vitamin E, flavonoids, linoleic acid, and OPCs. Fat-soluble vitamin E is absorbed from the gastrointestinal tract and is dependent on the presence of bile. It enters the blood stream via the lymph gland and is widely distributed in the cells. As much as several grams are stored in fatty tissues but most stays in the liver where it can be metabolised into an acid form and finally excreted in the urine.
The linoleic acid will need to be digested in the gut by enzymes such as lipases. The digestion process produces free fatty acids and monoglycerides which are easily absorbed by the intestinal wall cells.
The 95% OPCs present in grape seed extract means the antioxidant properties are made available in a highly absorbable form.
Vitamin E is very sensitive to oxidation, particularly in the presence of heat and alkali. Therefore frying or heating grape seed, or grape seed oil, will destroy the vitamin content. Heat and oxygenation will also destroy the antioxidant capacity of the supplement and also the essential fatty acid profile.