Volume 2 Number 3 August 2004

 

Review Articles
127 Lycopene and Human Health
A.VENKET RAO AND LETICIA G. RAO[ABSTRACT]
137 Antihypertensive Effect of Alpha Lipoic Acid Supplementation
SUDESH VASDEV, VICKI GILL, LINDA LONGERICH[ABSTRACT]
153 Cranberry (Vaccinium macrocarpon) Proanthocyanidins and Their Effects on Urinary Tract Infections
M.M. ZIRK, R.E. ALUKO AND C.G. TAYLOR[ABSTRACT]
161 Acute tryptophan depletion: Comparing the effects of an amino acid mixture with a gelatin-based protein in man and rats
A. BLOKLAND, C. LIEBEN, N.E.P. DEUTZ, AND J. SCHMITT[ABSTRACT]
169 Bioavailability of tryptophan from a single oral dose of a tryptophan-enriched peptide mixture in healthy men
ELIZABETH J. BRINK, ESTHER BOELSMA, JAN STEIJNS, AND HENK F.J. HENDRIKS[ABSTRACT]
177 Relationship Between Total Cholesterol and All Cause Mortality: Is There A Need For Lowering Total Cholesterol in The Japanese Populations?
TOMOHITO HAMAZAKI[ABSTRACT]
Book Reviews
189 Herbal Medicine—Chaos in the Marketplace
190 Tapping the Green Market—Certification & Management of Non-Timber Forest Products

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Current Topics in Nutraceutical Research, Volume 2, Number 3, pp. 127-137 (2004)
Lycopene and Human Health
A.VENKET RAO AND LETICIA G. RAO

ABSTRACT: There is evidence to suggest an association between oxidative stress induced by reactive oxygen species (ROS) and chronic diseases. Antioxidants, by virtue of their ability to mitigate the damaging effects of ROS, have generated interest in their use as chemopreventive agents for a number of chronic diseases. Lycopene is the most potent antioxidant carotenoid occurring naturally in many fruits and vegetables and predominantly in tomatoes and tomato products. There is considerable interest in the role of lycopene in the prevention of human diseases. Initial epidemiological observations suggested an inverse relationship between the intake of tomatoes and lycopene and the incidence of prostate cancer. There is now evidence to suggest a similar relationship between lycopene intake and the prevention of cancers of other sites, and cardiovascular disease. Several human intervention studies are now reported in the literature in support of the role of lycopene in chronic diseases. Recent studies are evaluating the effect of lycopene in the management of osteoporosis, hypertension, neurodegenerative disease and male infertility among other human diseases. Although the evidence in support of lycopene in disease prevention is mainly based on epidemiological studies, human clinical trials are now being undertaken and reported in the literature.

 

 

 

Current Topics in Nutraceutical Research, Volume 2, Number 3, pp. 137-153 (2004)

Antihypertensive Effect of Alpha Lipoic Acid Supplementation
SUDESH VASDEV, VICKI GILL, LINDA LONGERICH

ABSTRACT: In this review, we will discuss possible anti-hypertensive mechanisms of alpha lipoic acid. Essential hypertension is a worldwide health issue. People with hypertension are more likely to suffer from strokes, heart disease and kidney failure. Although its cause remains unknown, hypertension is thought to evolve from a combi-nation of genetic and lifestyle factors. Theories regarding its etiology suggest that underlying insulin resistance leads to altered glucose metabolism, elevated aldehydes such as methylglyoxal, alterations in nitric oxide-induced vasodila-tion and oxidative stress. High sugar and high salt diets have also been shown to influence the development of hypertension. Traditional antihypertensive treatments are non-specific and often result in a number of side effects and poor compliance. Alpha lipoic acid, an endogenous fatty acid, is a potent antioxidant that is both fat and water-soluble. Although there are no published studies to show its efficacy as an antihypertensive in human essential hyper-tensives, it has been shown to effectively lower blood pres-sure in rats with essential hypertension. Our research in hypertensive rats shows that alpha lipoic acid surpasses vitamin E, C and B6 in the control of blood pressure and associated adverse biochemical and histopathological changes. An examination of the biological properties of alpha lipoic acid and the published literature on in vitro and in vivo research suggests various mechanisms by which alpha lipoic acid can prevent hypertension and its complications. Since alpha lipoic acid has been used successfully for many years in individuals with diabetes to improve glucose metabolism and diabetic complications without untoward effects, and it effectively lowers blood pressure in hypertensive animals, we suggest that it may provide a safe and effective treatment for human essential hypertension and its cardiovascular complications.

 

 

 

Current Topics in Nutraceutical Research, Volume 2, Number 3, pp. 153-161 (2004)

Cranberry (Vaccinium macrocarpon) Proanthocyanidins and Their Effects on Urinary Tract Infections
M.M. ZIRK, R.E. ALUKO AND C.G. TAYLOR

ABSTRACT: Cranberries have been used for centuries as a therapeutic agent. The most popular curative effect of cranberries is its proposed benefits in preventing urinary tract infections (UTI). Benefits of cranberries have been claimed to be due to the acidity of the berry, and to the specific acids or sugars in the berry. Recently it has been shown that the beneficial effects of cranberries in prevention of UTI are due to two of its constituents, fructose and proantho-cyanidins (PAs), which function as anti-adherence agents. PAs are stable polyphenolic compounds and possess various qualities including antiviral, antibacterial, anti-adhesive, and antioxidant properties. The PAs found in cranberries are polymers of epicatechin. PAs prevent UTI by binding to epithelial cells lining the urinary tract and in the process block adhesion of Escherichia coli fimbriae. Administration of cranberry juice or cranberry concentrate tablets have been shown to reduce the recurrence and antibiotic requirements of UTI in women, though there is no conclusive evidence that it can be used as a curative agent. Cranberry tablets have been shown to have similar prophylactic effectiveness but more cost effective when com-pared to the juice. This review discusses the extraction, purification and bioactive properties of cranberry PAs.

 

 

 

Current Topics in Nutraceutical Research, Volume 2, Number 3, pp. 161-169 (2004)

Acute tryptophan depletion: Comparing the effects of an amino acid mixture with a gelatin-based protein in man and rats
A. BLOKLAND, C. LIEBEN, N.E.P. DEUTZ, AND J. SCHMITT

ABSTRACT: In this paper we describe the biochemical effects of an amino acid mixture (AA) and a gelatine-based protein meal (GP) on tryptophan (TRP) levels in man and rats. It was found that the AA mixture induced a substantial decrease in the plasma TRP level in man, whereas only a modest depletion was found in adult rats. A GP mixture induced a substantial decrease in both man and rat. On basis of the differences between the methods and the species, it is suggested that plasma TRP levels can be lowered by different methods but that each method has advantages and disadvantages. Although both methods lower plasma TRP, there seems to be no complete specificity of both methods. It is suggested that the specific effects of 5-HT depletion on brain function requires should preferably be tested with different TRP depletion methods.

 

 

 

 

Current Topics in Nutraceutical Research, Volume 2, Number 3, pp. 169-177 (2004)

Bioavailability of tryptophan from a single oral dose of a tryptophan-enriched peptide mixture in healthy men
ELIZABETH J. BRINK, ESTHER BOELSMA, JAN STEIJNS, AND HENK F.J. HENDRIKS

ABSTRACT: The aim of the study was to investigate the bioavailability of tryptophan (Trp) from a Trp-enriched peptide mixture in healthy men. A second objective was to investigate the effect of this Trp-enriched protein hydrolysate on potential parameters of serotonergic activity: serum serotonin, melatonin and prolactin, and urinary 5-hydroxyindol-acetic acid and 6-sulfatoxymelatonin. Glucose and insulin were measured as the placebo consist-ed of orange juice with added glucose. The study was a randomised, double blind, placebo-controlled, four-way crossover trial in eight healthy male subjects. Treatments consisted of a single oral load of a Trp-enriched protein hydrolysate containing 500 mg L-Trp, 500 mg L-Trp plus addition of a mixture of amino acids having the same com-position as in the hydrolysate, 500 mg L-Trp, and placebo. Before and after ingestion blood and urine were collected during a period of 4 hours. The Trp-enriched protein hydrolysate increased the plasma Trp/LNAA ratio by about 70% at 60 to 90 min after ingestion. All three Trp treat-ments induced a comparable plasma Trp-response demonstrating that Trp is readily available for the body inde-pendent of whether it was peptide-bonded or in free amino acid form. None of the Trp treatments affected serum serotonin, prolactin, melatonin and insulin concentrations, as well as urinary 5-hydroxyindol-acetic acid and 6-sulfa-toxymelatonin concentrations during the 4-hour measurement period in the morning.

 

 

 

 

Current Topics in Nutraceutical Research, Volume 2, Number 3, pp. 177-189 (2004)

Relationship Between Total Cholesterol and All Cause Mortality: Is There A Need For Lowering Total Cholesterol in The Japanese Populations?
TOMOHITO HAMAZAKI

ABSTRACT: In Japan, the health risk from hypercholesterolemia has been overemphasized for years. However, all of the recently performed large-scale epidemiological studies showed that higher cholesterol levels, like 240-260 mg/dL (6.2-6.7 mmol/L) or 240-280 mg/dL (6.2-7.3 mmol/L), are safer than lower cholesterol levels in terms of all-cause mortality. Some epidemiological studies showed no upper limits of benefit from serum cholesterol levels; in other words, the higher is the cholesterol level, the better. These observations are understandable in Japanese population, where mortality from coronary heart disease (CHD) is rather low compared with Western countries. The low mortality from CHD is partly explained by large fish consumption and lower body mass indexes of the Japanese population. Therefore, treating subjects with 240 to 260 mg/dL of cholesterol faces the paradox of treating those who are least likely to die. When serum cholesterol levels are believed to be high, dietary treatment is often recommended. An observational study recently performed in Japan showed that cholesterol-reducing diets might increase the risk of acute myocardial infarction nearly 3 times. Although Japanese market for statins (3-Hydroxy 3-methyl glutaryl-CoA reductase inhibitors) for treatment of hypercho-lesterolemia exceeds 3 billion US$ per annum, there is no hard evidence about the efficacy of statins in Japan. To further test the validity of our current observations, a meta-analysis of clinical data on the relationship between all cause mortality and total cholesterol is warranted. Until then, it is probably meaningless to develop nutraceuticals targeting hypercholesterolemia in Japan.