The findings of the study are consistent with a treatise that I published several years ago on garlic (Garlic: Medicinal Food or Nutritious Medicine? Robert A. Nagourney, Journal of Medicinal Food, 1998). In this study, I examined the history of garlic, as well as its chemistry and its medicinal properties. In addition to its anti-cancer properties, garlic is antibacterial, antiviral, antifungal, lowers blood pressure, reduces the risk of blood clots, lowers cholesterol and may serve as an anti-aging nutrient.
Where the recent study struck chord was its concordance with my strong recommendation from that 1998 article that we consume fresh garlic over the other preparations. The aged garlic extracts, dried garlic and garlic oil preparations lack the most important chemical constituent of all - allicin. Allicin, also known diallyl disulphide oxide (2-propanethiol sufinate) imparts the characteristic odor to garlic.
It is only formed when the precursor alliin is enzymatically converted to the allicin via the action of the enzyme alliinase. Once allicin is exposed to excess heat or oxygen it undergoes a variety of conversions that lead to diallyl sulfone as well the diallyl di, tri, and tetra sulfides.
These compounds, though biologically active, do not carry the potency of allicin. It is for this reason that I have, over the past two decades, urged my patients, family and friends to consume fresh garlic as a foodstuff. Indeed as I write in my book, Outliving Cancer, our family consumes the equivalent 2 - 3 liters of fresh garlic a month.
The history of garlic as a medicinal is indeed rich. And it was Gallen, in 130 AD, who described it as “Theriacum rusticorum” (the common man’s cure all). I am pleased that two millennia later Chinese cancer researchers have provided additional data to support his prescient observation.