Juvenon Health Journal volume 7 number 7 july 2008
By Benjamin V. Treadwell, Ph.D.
Eat your veggies! Why repeat one of your mother’s favorite mantras? Though we all know the importance of fruits and vegetables in our daily diet, now we have even more evidence of their benefits. There is mounting evidence to support the role of broccoli, Brussels sprouts and cabbage, as well as other cruciferous vegetables, in cancer prevention.
Is this just another ploy to get us to consume what many simply don’t like? Studies of populations whose diet regularly includes cruciferous vegetables (CVs’) have reported a significant decrease in the incidence of different forms of cancer, when compared to populations who largely avoid this type of plant-derived food.
But how can a vegetable inhibit cancer growth? Recent experimental work, summarized below, may help answer this question. Once we understand how CVs may help protect our health, will we be ready to listen to our mothers?
Picture laborious hours at the lab bench, grinding-up cruciferous vegetables, then separating and purifying their chemical constituents. With that kind of research, scientists identified a family of compounds contained in the vegetables, known as isothiocyanates.
These nutrients piqued the investigators’ interest. They had the unique capacity to interact with certain key cellular components involved in the regulation of cellular growth and protection from toxic substances. This capacity led the researchers to theorize that one or more of the isothiocyanates could be the anti-cancer agent in cruciferous vegetables.
One member of the isothiocyanate family, sulforaphane, is getting a lot of attention lately. It is present in high levels in broccoli (highest in broccoli sprouts). Research has shown this nutrient to be capable of interacting with key cellular constituents (proteins) to turn on specific sets of genes. These genes are believed to be involved in protecting our bodies and DNA from damage by environmental carcinogens and free radicals. Some of this damage has been linked to cancer.
In Vitro vs. In Vivo
It looks like isothiocyanates could be the answer to how cruciferous vegetables may improve our health and inhibit cancer growth. Not so fast! The early work was carried out in cell culture (in vitro) and not with animal or human studies (in vivo). Although examining the effects of nutrients and other compounds in vitro often leads to important discoveries, it can also produce misleading results.
Take adding sulforaphane to cells in culture, for example. These experiments have demonstrated interaction with a cellular switch, keap-1, which activates a portion of the genetic code, instructing the cell to produce specific agents that protect against potential cancer-causing chemicals. But it seems unlikely that experiments with animals, including humans, will produce the same results.
Why? The levels of sulforaphane introduced to the cell cultures could not be duplicated in vivo, even if subjects ingested very large quantities of cruciferous vegetables. Plus, it turns out the amount of sulforaphane actually entering the blood stream, via the digestive system, may be too low to elicit a response after reacting with and being neutralized by glutathione, another cellular nutrient.
Bridging the Gap
Is it possible to bridge the gap between the cell culture and animal studies? As a matter of fact, a current article presents human study results that appear to support the cancer-inhibiting properties of cruciferous vegetables.
A group of investigators examined the effects of a broccoli-enriched diet as opposed to a pea-enriched diet (control) on the expression of specific genes in prostate tissue taken at biopsy from men suspected of prostate cancer. The men were fed the diets for a 12-month period. At 6 and 12 months, biopsied tissue samples were examined for genetic changes.
The tissues from the pea diet group showed some variation in gene activity, but far less as compared to the broccoli diet group. Further analysis determined that most of the broccoli-diet genetic changes were in the direction of reducing cellular growth and increasing cellular death, both of which would result in the inhibition of cancer growth.
The authors of this study propose the following mechanism with broccoli. The isothiocyanates, such as sulforaphane, are first taken up by the cells of the digestive system (enterocytes) and transported into the blood stream. Because there is a much lower concentration of glutathione in the blood stream, relative to the interior of most cells, there is less likelihood of it neutralizing sulforaphane. Moreover, the blood contains a specific enzyme (GSTM1) that can dislodge any glutathione that binds to the sulforaphane, freeing more of it to act on specific blood proteins.
In fact, the researchers present evidence that the sulforaphane reacts with a number of specific blood-borne growth factors (EGF, TGF beta, and insulin), altering their biochemical properties. These growth factors, in turn, are responsible for altering the genetic activity in the broccoli diet group. The investigators theorize that this gene alteration favors inhibition of cancer cell growth.
Those who propose the mechanism described earlier – interaction with the keap 1 cellular switch – for the health benefits of sulforaphane may also be correct. Under certain conditions, such as may occur with age, some health problems or exposure to toxins, the cellular concentrations of glutathione may be reduced to a level at which it doesn’t react with/neutralize sulforaphane, allowing the activation of cell-protective genes.
CVs Bottom Line
Whatever the mechanism of action, the research seems to indicate real cancer-inhibiting benefits for one or more nutrients in cruciferous vegetables. The anecdotal evidence from populations who consume more CVs seems to support eating these veggies. Not only is regularly including CVs’ in your diet likely to improve your health, but it will also make your mother happy.
In the July 2008 issue of PloS ONE, a group of European researchers, associated with several universities and laboratories in the United Kingdom and Italy, published “Broccoli Consumption Interacts with GSTM1 to Perturb Oncogenic Signaling Pathways in the Prostate.” The article details a 12-month experiment to study the effects of a broccoli-enriched diet on cancer growth in the prostate.
This study provides experimental evidence, obtained in humans (in vivo), to support observational studies that diets rich in cruciferous vegetables may reduce the risk of prostate cancer. The investigators also identify a potential mechanism for this benefit.
In the experiment, male volunteers were randomly assigned to either a diet enriched with broccoli or the same diet with peas (control) substituted for broccoli. Biopsies of prostate tissue, after six and 12 months, demonstrated a much greater change in gene expression in the broccoli group, particularly in genes under the control of several growth factors (TGF beta, EGF, and insulin).
The investigators hypothesized that the greater change in gene expression is due to the action of specific nutrients contained in broccoli, the isothiocyanates, which include a family of related compounds, one of which is sulforaphane. They demonstrated that sulforaphane is capable of reacting with the growth factors and altering the signaling pathways of one or more of them.
This change favors the alteration of gene expression in prostate tissue to inhibit the growth of cancer cells.
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.
Dr. Treadwell answers your questions about Juvenon™ Cellular Health Supplement
QUESTION: I know the answer to my question is going to be check with your physician. But I wondered, in general, if a person is on Zocor and Toprol, would he or she be able to eventually discontinue these medications if taking Juvenon Cellular Health Supplement? I ask this question because I know that they may have negative side effects, as many medications can. What is your opinion, please? Thank you. – K
ANSWER: There is no experimental evidence that the Juvenon Cellular Health Supplement will be an effective substitute for Zocor, the cholesterol-lowering statin drug, or Toprol, a beta blocker often prescribed for hypertension.
Zocor seems to be a pretty safe drug for most people. If you are experiencing negative effects, you may want to consult your health professional about red yeast rice as a cholesterol-reducing alternative. Although effectiveness seems to vary between brands, recent reports indicate this natural supplement may improve lipid profile, even more so when taken with fish oil containing the omega 3 fatty acids.
As to blood pressure concerns, losing a few pounds can have a significant effect on lowering blood pressure and improving overall health. The Mediterranean diet (low salt) and exercise may also be helpful in maintaining cardiovascular health.
Benjamin V. Treadwell, Ph.D., is a former Harvard Medical School associate professor and member of Juvenon’s Scientific Advisory Board.