Tempe, Tofu, and Amyloid-ß 1-40 Serum Levels in Ovariectomized Rats.

BACKGROUND: Estrogens have been found to reduce amyloid-ß (Aß) levels, a risk factor associated with dementia. We hypothesized that phytoestrogenic soybean products such as tempe and tofu might show similar effects. OBJECTIVE: The aim of this study were to analyze the effect of tempe and tofu flour on Aß1-40 serum levels in ovariectomized rats. METHODS: This research was conducted on female Sprague Dawley rats, aged 12 months. Before the intervention rats underwent ovariectomy (OVx) and were grouped into 5 intervention groups which were given tempe flour, tofu flour, estradiol, or casein as an active control. There was also a non-OVx control group which was fed a normal diet. RESULTS: The intake of tempe and tofu flour decreased Aß serum levels in all estrogen and phytoestrogenic treatment groups, offsetting effects of OVx (but not in the casein group, where Aß levels rise). CONCLUSION: The tempe flour group showed the strongest decrease in serum Aß levels compared to the other groups. Future studies should investigate whether tempe can reduce Aß levels in patients with dementia.

Comparing the effect of tempe flour and tofu flour consumption on estrogen serum in ovariectomized rats.

Estrogen decreasing during menopause can create problems in the cardiovascular organs, brain, urogental tract, and bone. Estrogen replacement therapy (ERT) can be used to increase estrogen levels. However, side-effects including breast cancer may limit their use. Tempe and tofu are natural plat-based foods which contain phytoestrogens. The aim of this research was to compare estrogen serum levels in ovariectomized rats given tempe flour and tofu flour. This research was conducted on female rats, aged 12 months (n = 72 rats). Rats were grouped into 5 groups: tempe flour, tofu flour, estradiol, casein and non-ovariectomized. The intervention was carried out for two months with three observation points; i) in the second week, ii) fifth week and iii) eighth week. Estrogen serum analysis was done by ELISA (Estradiol EIA-2693). The mean and the differences between treatment groups were analysed using one way ANOVA with post hoc polynomial contrasts (LSD). The highest estrogen serum in the second week intervention was found in the estradiol group followed by the tempe flour, tofu flour, non-ovariectomized and casein groups, respectively. The tempe flour group had the highest mean serum estrogen levels in the fifth week, followed by the estradiol group, non-ovariectomized group, tofu group and casein group. At the eighth week of intervention, the highest estrogen serum level was found in the tempe flour group followed by the estradiol group, tofu flour group, non ovariectomy group and casein group. Interventions in the fifth and eighth weeks showed significant differences between groups (p < 0.05). It was concluded that tempe flour rendered twice the serum estrogen level compared to tofu flour. Further research is needed in the form of clinical trials to prove that effect in humans.

Nutrition research in cognitive impairment/dementia, with a focus on soya and folate.

Observational studies and treatment trials investigating nutrition and cognitive function, with a focus on folate and soya and dementia, were reviewed. Data suggested that effects of folic acid based interventions may only be shown before cognitive decline is evident and/or if people are folate deficient. In older people in Indonesia, Hawai'i and China, tofu, which can contain high levels of phytoestrogens, was found to increase dementia risk. This association was not mediated by a vegetarian diet, socioeconomic status, formaldehyde, thyroid function, or loss of teeth. On the other hand, human observational and animal treatment studies suggested that tempe, a fermented soya product containing phytoestrogens and folate, reduced dementia risk and improved memory. High oestrogen levels were found to increase dementia risk in older women. However, in women with adequate serum folate, high oestrogen levels did not confer additional dementia risk and may protect ageing neurons. In conclusion, reviews seem to suggest that folic acid interventions are only effective on cognitive outcomes in people who are folate deficient and do not have cognitive impairment. Frequent consumption of tofu may have detrimental effects on memory and increase dementia risk in older East Asian people, while tempe may reduce these risks. Possibly folate in tempe offsets the potential negative effects of oestrogenic compounds on ageing neurons.