The status of plasma homocysteine and related B-vitamins in healthy young vegetarians and nonvegetarians

Huang, Yann-Chang; Chang, Shang‐Jen; Chiu, Yu Ting; Chang, Han; Cheng, Chien Hsiang

doi:10.1007/s00394-003-0387-5

Cited by 50 publications

(47 citation statements)

References 29 publications

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“…Our data also showed that the vegetarians had a significantly higher level of homocysteine than omnivores in both men and women. This result is similar to that of previous studies on vegetarians carried out in Taiwan and elsewhere (Krajèovioèvá-Kudláèková et al, 2000;Hung et al, 2002;Herrmann et al, 2003;Huang et al, 2003;Su et al, 2006). In experimental studies, homocysteine has been shown to stimulate vascular smooth muscle cells to proliferate and to synthesize collagen, which is a hallmark of atherogenesis.…”

Section: Conventional Cardiovascular Risk Factorssupporting

confidence: 90%

“…In Taiwanese vegetarians, the intake and mean plasma concentration of vitamin B 12 were lower than in omnivores, which leads to an increase in plasma homocysteine concentration. Furthermore, vitamin B 6 and folate have little effect on plasma homocysteine concentration when individuals have an adequate vitamin B 6 and folate status (Huang et al, 2003). In The Swiss Heart Study, homocysteine-lowering therapy with folic acid, vitamin B 12 and vitamin B 6 significantly decreases the incidence of major events after percutaneous coronary intervention (Schnyder et al, 2002).…”

Section: Vitamin Supplementationmentioning

confidence: 99%

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Total cardiovascular risk profile of Taiwanese vegetarians

Chen

Lin

et al. 2007

Eur J Clin Nutr

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Background: Although the health benefits of vegetarian diets have been well documented among Western population, there are geographic differences of vegetarian diets and the health benefits of the Taiwanese vegetarian diet have not been studied extensively. In addition to conventional risk factors, homocysteine and high-sensitivity C-reactive protein (hs-CRP) levels have been found to predict first atherothrombotic events. We undertook this study to examine the total risk profile of Taiwanese vegetarians. Methods: A total of 198 healthy subjects (99 vegetarians and 99 omnivores) were recruited. Fasting blood samples were analyzed for glucose, cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), white blood cell count, hs-CRP and homocysteine. Results: There was no significant difference in age, body mass index, blood glucose, white blood cell count, triglyceride and HDL-C between the two groups. The vegetarian group had significantly more females (65.7 vs 46.5%); lower body weight (58.66711.13 vs 62.88712.24 kg); shorter height (159.1477.88 vs 162.53 78.14 cm); lower total cholesterol (184.74733.23 vs 202.01741.05 mg/dl); and lower LDL-C (119.63731.59 vs 135.89739.50 mg/dl). Hs-CRP was significantly lower (0.1470.23 vs 0.2370.44 mg/dl, P ¼ 0.025), whereas homocysteine was significantly higher (10.9776.69 vs 8.4472.50 mmol/l, P ¼ 0.001) in vegetarians than omnivores. Conclusions: Taiwanese vegetarians have lower total cholesterol, LDL-C and hs-CRP levels, and higher homocysteine levels than omnivores. Owing to different predictive value of each risk factor, the Taiwanese vegetarians had a better cardiovascular risk profile than omnivores. Whether the Taiwanese vegetarian diet should be supplemented with vitamin B 12 to lower serum homocysteine level remains to be addressed.

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Section: Conventional Cardiovascular Risk Factorssupporting

confidence: 90%

Section: Vitamin Supplementationmentioning

confidence: 99%

Total cardiovascular risk profile of Taiwanese vegetarians

Chen

Lin

et al. 2007

Eur J Clin Nutr

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“…Before starting the experiments, all rats were acclimated to the facility for 5 d and given free access to water and a 25% casein diet. In the present study, seven experimental diets (A-G) differing in casein level (10,30, and 50%) and differing in methionine level together with or without glycine ϩ serine supplementation were used (Table 1). These diets were abbreviated as follows:…”

Section: Animals and Dietsmentioning

confidence: 99%

Hepatic Cystathionine β-Synthase Activity Does Not Increase in Response to Methionine Supplementation in Rats Fed a Low Casein Diet: Association with Plasma Homocysteine Concentrations

Ohuchi

Morita

Mori

et al. 2009

J Nutr Sci Vitaminol

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Summary To elucidate the mechanism by which moderate and high protein diets fail to increase plasma homocysteine concentration despite dietary methionine levels being higher, rats were fed diets with graded levels (10, 30, and 50%) of casein or low casein diets supplemented with methionine at levels of 0.5 and 1.0% together with or without glycine ϩ serine, which corresponded to moderate and high casein diets with respect to these amino acids, for 14 d. The plasma homocysteine concentration significantly decreased with an increase in dietary casein level, whereas it significantly increased with an increase in dietary methionine level when the low casein diet was supplemented with methionine. Supplementation with glycine ϩ serine significantly suppressed the elevation of plasma homocysteine concentration due to methionine supplementation, but it could not decrease plasma homocysteine concentration to the levels in rats fed corresponding casein diets. Increased concentrations of hepatic S -adenosylhomocysteine and homocysteine due to methionine supplementation were also significantly suppressed by glycine ϩ serine. The activity of hepatic cystathionine ␤ -synthase (CBS) did not increase in response to methionine supplementation, while it significantly increased with an increase in dietary casein level. In contrast, the activity of hepatic betaine-homocysteine S -methyltransferase (BHMT) significantly increased with increase in both dietary casein level and dietary methionine level. Hepatic levels of mRNA for CBS and BHMT were parallel to the enzyme activities. The results suggest that, in contrast to methionine-supplemented low casein diets, moderate and high casein diets avoid increasing plasma homocysteine concentration through dual mechanisms, greater supply of glycine ϩ serine and an increase in CBS activity. Key Words dietary methionine level, dietary casein level, plasma homocysteine, cystathionine ␤ -synthase, betaine-homocysteine S -methyltransferase Homocysteine is known to be one of the intermediates of methionine metabolism ( Fig. 1) ( 1 ), but a number of studies have suggested that an elevated plasma homocysteine concentration might be an independent risk factor for cardiovascular disease ( 2 -4 ). The plasma homocysteine concentration is affected by various factors such as genetic, nutritional, physiological, clinical, and lifestyle factors. Of these factors, genetic and nutritional factors are thought to have a greater influence on the plasma homocysteine concentration. For instance, deficiencies of folate, vitamin B12, and vitamin B6 cause hyperhomocysteinemia, since these vitamins participate in the metabolism of homocysteine. The relationship between protein intake and plasma homocysteine concentration is one of the subjects attracting much attention, since the intake of protein is usually associated with the intake of methionine, the sole precursor of homocysteine. In humans, high protein diets increased postprandial plasma homocysteine concentration ( 5 -7 ), while high protein diets did not al...

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“…In contrast, sustained intakes of high protein diets did not alter plasma homocysteine concentration in some interventional studies ( 6 , 7 ). Several observational studies have shown that there was no significant correlation between plasma homocysteine concentration and protein intake ( 8 -11 ), whereas a significantly positive ( 12 ) or negative ( 13 ) correlation was found between the two variables in some studies. Thus, the results of previous human studies on the relationship between plasma homocysteine concentration and protein intake are not consistent, and it appears that a consensus has not yet been established.…”

mentioning

confidence: 97%

High Casein Diet Decreases Plasma Homocysteine Concentration in Rats

Ohuchi

Matsumoto

Morita

et al. 2009

J Nutr Sci Vitaminol

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Summary Experiments were conducted to clarify the relationship between dietary protein level and plasma homocysteine concentration in rats. Male Wistar rats were fed diets differing in casein level from 5 to 50% for 14 d (Expt. 1). Plasma total homocysteine concentration was positively correlated with dietary casein level in the range of 5 to 10% but inversely correlated with dietary casein level in the range of 10 to 50%. Hepatic cystathionine ␤ -synthase (CBS) and betaine-homocysteine S -methyltransferase (BHMT) activities and renal CBS activity increased in response to dietary casein level in the range of 10 to 50%, whereas hepatic serine and betaine concentrations decreased with increasing dietary casein levels. When rats were fed the 10% casein diet or 10% casein ϩ 17.2% amino acid mixture diet for 14 d, plasma homocysteine concentration was significantly lower in rats fed the amino acid mixture-added diet than in rats fed the 10% casein diet (Expt. 2), indicating that the hypohomocysteinemic effect of high casein diets was elicited by amino acids, not by casein contaminants. The degree of increase in plasma homocysteine concentration caused by dietary supplementation with 0.75% L -methionine was significantly lower in rats fed the 40% casein diet than in rats fed the 10% casein diet (Expt. 3). These results indicate that high casein diets do not increase but rather decrease plasma homocysteine concentration and cause resistance to hyperhomocysteinemic treatment, and suggest that such effects of high casein diets are mediated at least by increased activities of CBS and BHMT. Key Words dietary casein level, homocysteine, methionine, cystathionine ␤ -synthase, betaine-homocysteine S -methyltransferase Homocysteine is one of the intermediates of methionine metabolism. A number of studies have suggested that an elevated plasma homocysteine concentration might be an independent risk factor for cardiovascular disease ( 1 -3 ). It has been shown that plasma homocysteine concentration is affected by several factors such as genetics, physiology, lifestyle, nutrition, clinical factors, and drugs ( 1 -3 ). Genetic factors and nutritional conditions are thought to have a greater influence on plasma homocysteine concentration. For instance, deficiencies of the vitamins such as folate, vitamin B-6, and vitamin B-12 increase plasma homocysteine concentration, because folate and vitamin B-12 are involved in the remethylation of homocysteine and vitamin B-6 is involved in the formation of cystathionine.Recently attention has also been focused on the effect of dietary proteins on plasma homocysteine concentration, since the intake of methionine, the sole precursor of homocysteine, is usually associated with the amount and type of dietary proteins ingested. In humans, it has been shown that a single ingestion of a high protein meal increased postprandial plasma homocysteine concentration ( 4 , 5 ), although the effect of the high protein meal was smaller than that of an equivalent amount of free methionine ( 5 ). In contrast,...

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The status of plasma homocysteine and related B-vitamins in healthy young vegetarians and nonvegetarians

Cited by 50 publications

References 29 publications

Total cardiovascular risk profile of Taiwanese vegetarians

Total cardiovascular risk profile of Taiwanese vegetarians

Hepatic Cystathionine β-Synthase Activity Does Not Increase in Response to Methionine Supplementation in Rats Fed a Low Casein Diet: Association with Plasma Homocysteine Concentrations

High Casein Diet Decreases Plasma Homocysteine Concentration in Rats

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