In 2004 there was a study:
HIGH ABSORPTION BUT VERY LOW BIOAVAILABILITY OF ORAL RESVERATROL
Thomas Walle, Faye Hsieh, Mark H. DeLegge, John E. Oatis, Jr., and U. Kristina Walle Department of Cell and Molecular Pharmacology and Experimental Therapeutics (T.W., J.E.O., U.K.W.) and Digestive Disease Center (M.H.D.), Medical University of South Carolina, Charleston, South Carolina; and Amgen, Inc., Thousand Oaks, California (F.H.)Received June 7, 2004; accepted August 26, 2004
It stated the following:
“The absorption of a dietary relevant
25-mg oral dose was at least 70%, with peak plasma levels of
resveratrol and metabolites of 491 90 ng/ml (about 2 M) and a
plasma half-life of 9.2 0.6 h. However, only trace amounts of
unchanged resveratrol (<5 ng/ml) could be detected in plasma.
Most of the oral dose was recovered in urine, and liquid chromatography/ mass spectrometry analysis identified three metabolic pathways, i.e., sulfate and glucuronic acid conjugation of the phenolic groups and, interestingly, hydrogenation of the aliphatic double bond, the latter likely produced by the intestinal microflora.
Extremely rapid sulfate conjugation by the intestine/liver appears to be the rate-limiting step in resveratrolï¿½??s bioavailability. Although the systemic bioavailability of resveratrol is very low, accumulation of resveratrol in epithelial cells along the aerodigestive tract and potentially active resveratrol metabolites may still produce cancerpreventive and other effects.”
In 2006 we had a paper published by David Sinclair called:
Therapeutic potential the in vivo evidence - Joseph A. Baur and David A. Sinclair
In this paper we can quote the following:
The efficacy of low doses (for example, 200 Î¼g per kg (body weight)daily in a rat model of colon carcinogenesis15) suggests that even the concentration of resveratrol obtained from dietary sources, such as red wine, could be therapeutic in some cases. At higher, but pharmacologically achievable doses, protective effects of resveratrol are more frequently observed, and the results are more dramatic. For example, a daily dose of 40 mg per kg (body weight) increased the survival of mice with subcutaneous neuroblastomas from 0% to 70%16.
In his conclusions in the same paper we can also quote the following:
“In mammals, there is growing evidence that resveratrol can prevent or delay the onset of cancer, heart disease, ischaemic and chemically induced injuries, diabetes, pathological inflammation and viral infection. These effects are observed despite extremely low bioavailability and rapid clearance from the circulation.”
“Moreover, administering a daily dose to a human weighing 75 kg with 100 mg per kg (body weight) of resveratrol would require 2.7 kg of resveratrol a year”
basically 7 grams for a person weighing around 154lbs