Possible effects on blood pressure
As we age there is a loss of arterial elasticity, which is a cause of high blood pressure. Another major cause of hypertension is an enzyme secreted by the kidneys called angiotension-converting enzyme (ACE).
Angiotension-converting enzyme (ACE) has been classically associated with the renin-angiotension system, which regulates peripheral blood pressure. People with high blood pressure are often prescribed drugs such as Zestril, Capoten and Vasotec, referred to as "angiotension-converting enzyme inhibitors" or ACE inhibitors for short. By blocking the effects of ACE, blood pressure can be brought under control in the majority of people with hypertension.
Whey peptides, known as Lactokinins, were recently shown to be mild ACE inhibitors in vitro. While they do not have the inhibitory potency of the drugs mentioned above used in the treatment of hypertension, the researchers concluded, "…these naturally occurring peptides may represent nutraceutical/functional food ingredients for the prevention/treatment of high blood pressure." Clearly more research is needed, but if confirmed by future research, this could be yet another use for whey proteins.Effects on hepatitis
Considering the importance of glutathione (GSH) for liver function and the resulting oxidative stress that accompanies hepatitis, researchers looked to see what affect high quality whey would have on laboratory indices of viral hepatitis and liver function. In an open clinical study researchers looked at the efficacy of whey protein vs. casein fed to 25 patients suffering from either hepatitis B or C. Twelve grams of either whey or casein as food was given twice a day, in the morning and evening, for 12 weeks. The researchers looked at:
- Serum alanine aminotransferase (ALT)-an indicator of liver stress and function
- Serum glutathione (GSH)
- Serum lipid peroxide levels-an indicator of oxidative stress
- Interleukin (IL)-2 levels-a pro inflammatory interleukin
- Natural killer (NK) cell activity
Amazingly, after the 12-week period, the hepatitis B group getting the whey showed a "significant" decrease in serum lipid peroxides, with an increase in plasma glutathione levels in five of the eight subjects. A decrease was shown in Interleukin (IL)-2 levels with a significant increase in natural killer (NK) cell activity. Most important, there was a drop in serum alanine aminotransferase (ALT) activity, indicating reduction in liver damage caused by the hepatitis B virus. Unfortunately, there were no significant changes in the 17 patients with hepatitis C. Based on this one study, it would appear that whey might be a safe therapy for improving liver function in patients with chronic hepatitis B but not hepatitis C. Since the mechanisms of whey's actions would appear to benefit hepatitis C patients, we eagerly look forward to the results of additional clinical studies.Whey protects the stomach as well as antiulcer drugs
An ever-growing body of studies has shown that whey proteins and their subfractions have a wide range of biological activities. One area that has not been fully explored is the potential role of whey protein in the protection of the gastrointestinal system. One recent study investigated the effect of either whey or casein protein on gastric mucosal injury by using two ulcer models in rats. Gastric mucosal injury was induced by either alcohol (ethanol) or water-immersion restraint stress where the poor rats are put in water at 23 degrees C for 7 hours.
Whey or casein was given to the rats 30 min before the induction of gastric injury. Whey is a complex protein made up of many smaller protein subfractions (peptides). Each of the subfractions found in whey has its own unique biological properties. Interestingly, one of the major subfractions in whey (alpha-lactalbumin) was shown to have a "…marked protective effect against ethanol-induced gastric injury, with the same potency as that of the typical antiulcer agent, Selbex," according to the researchers. As expected, whey protein isolate (WPI) also protected against gastric injury, as it contains high amounts of alpha-lactalbumin, while casein showed no effect.
Alpha-lactalbumin showed dose-dependent protection against gastric injury caused by alcohol or stress. The effect appears to be in part due to prostaglandin synthesis caused by the alpha-lactalbumin found in the whey, but effects on GSH in tissues probably played a key role. The researchers concluded, "These results indicate that alpha-LA (a component found in whey) has marked antiulcer activity as an active component of cow's milk protein, and suggest that alpha-LA intake may serve to protect against gastric mucosal injury, in part through endogenous prostaglandin synthesis." Again, human studies are needed to come to definitive conclusions about the role a high quality whey protein may play in the development and protection against ulcers and other pathologies/injuries to the stomach, but it's a potentially important finding to the millions of people with various gastrointestinal problems.Chronic fatigue
Chronic fatigue syndrome (CFS) has been a vexing problem for both clinicians and patients alike. Finding clear associations between people who suffer from CFS has been difficult. There have been, however, some similarities among groups of people with CFS. In a large proportion of people with CFS, abnormalities are often found in both humoral and cellular immunity. The exact cause of this is not fully understood. One fairly consistent finding in people with CFS is am impaired lymphocyte (T-cell) responses to a challenge. That is, the lymphocyte does not respond appropriately or rapidly when presented with an immune challenge. As early research has shown, the ability of lymphocytes to react to an immune challenge is directly related to their GSH status. Also, continued use of GSH by lymphocytes may lead to cellular GSH depletion and immune failure.
One hypotheses put forth by Dr. Bounous from the Department of Surgery at McGill University, is the idea that the competition for GHS precursors over time may lead to muscle fatigue (myalgia) and other symptoms associated with CFS. He states: "Because GSH is also essential to aerobic muscular contraction, an undesirable competition for GSH precursors between the immune and muscular systems may develop. It is conceivable that the priority of the immune system for the survival of the host has drawn to this vital area the ever-diminishing GSH precursors, thus depriving the skeletal muscle of adequate GSH precursors to sustain a normal aerobic metabolism resulting in fatigue and eventually myalgia."
Because whey is the most effective way to deliver precursors for GSH synthesis, as well as being shown to raise GSH levels in humans and animals, it is theorized that whey may be especially effective for people suffering from CFS. Although large-scale studies with CFS and whey have yet to be done, the idea makes perfect sense and it may be worth a try for people with CFS to use whey on a regular basis.Whey and performance
Finally, most athletes know of whey as a high quality protein with a very high biological value (BV) rating. It's no surprise that athletes and active people have made whey based protein supplements the best selling on the market. However, whey may in fact have direct effects on performance. Many studies have found that oxidative stress contributes to muscular fatigue and some studies have found the use of antioxidants may improve performance. As mentioned previously, GSH is the major intracellular water-soluble antioxidant in the body, which is involved in the recycling of other antioxidants.
Twenty healthy young adults (10 men, 10 women) were supplemented with either whey or casein for three months. The researchers looked at:
Muscular performance-as assessed by whole leg isokinetic cycle testing
Lymphocyte GSH levels-as a marker of tissue GSH
As one would expect, they found no baseline differences in peak power or work capacity between the whey and casein groups. However, after treatment, a follow-up on 18 subjects-nine who received the whey and nine who received the casein (considered a placebo in this study)-were analyzed. Both peak power and work capacity increased significantly in the whey group, with no changes found in the casein group. Lymphocyte GSH also increased by over 35% in the group receiving the whey with no change in the group getting casein.
The researchers concluded, "This is the first study to demonstrate that prolonged supplementation with a product designed to augment antioxidant defenses resulted in improved volitional performance." This along with previous studies make it clear that whey is the protein supplement of choice for athletes for a wide variety of reasons, one of which may be improved performance during endurance exercise.References
1. Am J Clin Nutr 2000 Jun;71(6):1536-1544.
2. Oral supplementation with whey proteins increases plasma glutathione levels of HIV-infected patients. Eur J Clin Invest 2001 Feb;31(2):171-8.
3. Lactokinins: whey protein-derived ACE inhibitory peptides. Nahrung 1999 Jun;43(3):165-7.
4. Nutritional therapy of chronic hepatitis by whey protein (non-heated). J Med 2000;31(5-6):283-302.
5. New biological function of bovine alpha-lactalbumin: protective effect against ethanol- and stress-induced gastric mucosal injury in rats. Biosci Biotechnol Biochem 2001 May;65(5):1104-11.
6. Competition for glutathione precursors between the immune system and the skeletal muscle: pathogenesis of chronic fatigue syndrome. Med Hypotheses 1999 Oct;53(4):347-9.
7. Effect of supplementation with a cysteine donor on muscular performance. Journal of Applied Physiology. 87(4):1381-5, 1999 Oct.
Will Brink is a well known medical, fitness and health writer for a variety of publications. He graduated from Harvard University with a degree in the natural sciences, and is a regular guest on national radio shows and a speaker at various conventions around the US. His articles on such topics as cancer, AIDS, weight loss, fitness and health can be found in Life Extension magazine as well as other related publications. He is also a consultant to major supplement companies, and regularly co-authors articles with different researchers from around the world. He is most noted for his articles and work with whey proteins and essential fatty acids in athletics and the treatment and prevention of various diseases. His new e-book, Diet supplements Revealed, can be found at www.AboutSupplements.com. He can be contacted at PO Box 480, Newton MA, 02159. Website: www.brinkzone.com E-mail: firstname.lastname@example.org