大豆食品と認知症の関係としては、
ネットでは、「認知症予防のために食べましょう！」という記事が多い。


しかし、体によいとされている一方で、海外では認知症との関係が問われているのである。

 

 

2000年、豆腐を多く食べる中年は認知症になる可能性が高いという報告があった。

 

J Am Coll Nutr. 2000 Apr;19(2):242-55.

Brain aging and midlife tofu consumption.

White LR¹, Petrovitch H, Ross GW, Masaki K, Hardman J, Nelson J, Davis D, Markesbery W.

 

Abstract

OBJECTIVE:

To examine associations of midlife tofu consumption with brain function and structural changes in late life.

METHODS:

The design utilized surviving participants of a longitudinal study established in 1965 for research on heart disease, stroke, and cancer. Information on consumption of selected foods was available from standardized interviews conducted 1965-1967 and 1971-1974. A 4-level composite intake index defined "low-low" consumption as fewer than two servings of tofu per week in 1965 and no tofu in the prior week in 1971. Men who reported two or more servings per week at both interviews were defined as "high-high" consumers. Intermediate or less consistent "low" and "high" consumption levels were also defined. Cognitive functioning was tested at the 1991-1993 examination, when participants were aged 71 to 93 years (n = 3734). Brain atrophy was assessed using neuroimage (n = 574) and autopsy (n = 290) information. Cognitive function data were also analyzed for wives of a sample of study participants (n = 502) who had been living with the participants at the time of their dietary interviews.

RESULTS:

Poor cognitive test performance, enlargement of ventricles and low brain weight were each significantly and independently associated with higher midlife tofu consumption. A similar association of midlife tofu intake with poor late life cognitive test scores was also observed among wives of cohort members, using the husband's answers to food frequency questions as proxy for the wife's consumption. Statistically significant associations were consistently demonstrated in linear and logistic multivariate regression models. Odds ratios comparing endpoints among "high-high" with "low-low" consumers were mostly in the range of 1.6 to 2.0.

CONCLUSIONS:

In this population, higher midlife tofu consumption was independently associated with indicators of cognitive impairment and brain atrophy in late life.

豆腐を良く食べる人は、あまり食べない人に比して、脳の委縮が1.6～2倍多いという結果である。

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2000年、日系のアメリカ人で、エストロゲンが認知症に関与していることが報告された。（大豆イソフラボンは、エストロゲン受容体と関与している。）

Arch Intern Med. 2000 Jun 12;160(11):1641-9.

Postmenopausal estrogen and estrogen-progestin use and 2-year rate of cognitive change in a cohort of older Japanese American women: The Kame Project.

Rice MM¹, Graves AB, McCurry SM, Gibbons LE, Bowen JD, McCormick WC, Larson EB.

Abstract

BACKGROUND:

The relation between estrogen and cognition among postmenopausal women remains controversial. Also uncertain is whether the proposed association varies between women taking unopposed estrogen and those taking estrogen combined with progestin.

OBJECTIVE:

To determine whether unopposed estrogen and combined estrogen-progestin use were associated with the rate of cognitive change in a cohort of older, Japanese American, postmenopausal women.

METHODS:

A prospective observational study in a population-based cohort of older Japanese Americans (aged > or =65 years) living in King County, Washington. Cognitive performance was measured in 837 women at baseline (1992-1994) and 2-year follow-up (1994-1997) examinations using the 100-point Cognitive Abilities Screening Instrument (CASI). Least squares means general linear models were used to estimate the 2-year rate of cognitive change according to categories of postmenopausal estrogen use.

RESULTS:

Approximately half of this cohort (n=455) had never used estrogen at any time since menopause, 186 were past users, 132 were current unopposed estrogen users, and 64 were current estrogen-progestin users. The majority of current estrogen users were taking conjugated estrogens, and all women receiving combined therapy were taking medroxyprogesterone acetate. After adjusting for age, education, language spoken at the interview, surgical menopause, and baseline CASI score, women who had never used postmenopausal estrogen improved slightly on the CASI scale (mean adjusted change, 0.79; SEM, 0.19). This change was significantly greater for current unopposed estrogen users (mean adjusted change, 1.68; SEM, 0.36; P=.04) and significantly worse for current estrogen-progestin users (mean adjusted change, -0.41; SEM, 0.50; P =.02) compared with never users. The improvement observed in past users (mean adjusted change, 1.12; SEM, 0.29) was intermediate between the changes for never users and current unopposed estrogen users and not significantly greater than that for never users (P=.35).

CONCLUSIONS:

Our findings support a modest beneficial association between current unopposed estrogen use and the rate of cognitive change. We also observed a modest detrimental association between current estrogen-progestin use and the rate of cognitive change. The clinical significance of these modest differences, however, is uncertain. Data from large, long-term randomized trials are required before applying this information to the clinical setting.

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2003年、大豆を摂取すると、イソフラボンを摂取できるため、記憶や認知機能が良くなると報告された。

Menopause. 2003 May-Jun;10(3):196-202.

Isoflavones and cognitive function in older women: the SOy and Postmenopausal Health In Aging(SOPHIA) Study.

Kritz-Silverstein D¹, Von Mühlen D, Barrett-Connor E, Bressel MA.

Abstract

OBJECTIVE:

This study examines the effects of a dietary supplement of isoflavones on cognitive function in postmenopausal women.

DESIGN:

Participants for this 6-month, double-blind, randomized, placebo-controlled clinical trial were women who were in good health, were postmenopausal at least 2 years, and were not using estrogen replacement therapy. Between July 24, 2000, and October 31, 2000, 56 women aged 55 to 74 years were randomized; 2 in the placebo group and 1 in the active treatment group did not complete the 6-month evaluation, and none withdrew because of adverse effects. Women randomized to active treatment (n = 27) took two pills per day, each containing 55 mg of soy-extracted isoflavones (110 mg total isoflavones per day; Healthy Woman: Soy Menopause Supplement, Personal Products Company, McNeil-PPC Inc., Skillman, NJ, USA). Women assigned to placebo (n = 26) took two identical-appearing pills per day containing inert ingredients. Cognitive function tests administered at baseline and follow-up included the following: Trails A and B, category fluency, and logical memory and recall (a paragraph recall test assessing immediate and delayed verbal memory).

RESULTS:

At baseline, all women were cognitively intact; there were no significant differences by treatment assignment in age, education, depressed mood, or cognitive function (all P values > 0.10). Compliance was 98% and 97%, respectively, in the placebo and treatment groups; all women took at least 85% of their pills. The women in the treatment group did consistently better, both as compared with their own baseline scores and as compared with the placebo group responses at 6 months. Comparisons of percentage change in cognitive function between baseline and follow-up showed greater improvement in category fluency for women on active treatment as compared with the case of those on placebo (P = 0.02) and showed (nonsignificantly) greater improvement on the two other tests of verbal memory and Trails B.

CONCLUSION:

These results suggest that isoflavone supplementation has a favorable effect on cognitive function, particularly verbal memory, in postmenopausal women.

 

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2005年、植物性エストロゲン食の摂取と認知症の関係を調べたところ、認知症に効果があるのはリグナンであり、イソフラボンではないという研究が報告された。

J Nutr. 2005 May;135(5):1190-5.

Higher dietary intake of lignans is associated with better cognitive performance in postmenopausal women.

Franco OH¹, Burger H, Lebrun CE, Peeters PH, Lamberts SW, Grobbee DE, Van Der Schouw YT.

Abstract

Data on the relation between phytoestrogens and cognitive function are still sparse. The purpose of this study was to examine the relation between the dietary intake of phytoestrogens and cognitive function in healthy postmenopausal women consuming a Western diet. We conducted a community-based survey among 394 postmenopausal women. Isoflavone and lignan intake was calculated from a validated FFQ. Cognitive function was evaluated using the Mini-Mental State Examination (MMSE). Data were analyzed using logistic regression with intact cognitive function defined as a score >/= 26 as the outcome variable. After adjustment for confounders, increasing dietary lignans intake was associated with better performance on the MMSE [OR and (95%CI): 1.49 (0.94-2.38)]. Results were most pronounced in women who were 20-30 y postmenopausal [2.02 (1.11-3.71)]. Isoflavone intake was not related to cognitive function. From our results we conclude that higher dietary intake of lignans is associated with better cognitive function in postmenopausal women.

 

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2008年、豆腐がインドネシアの高齢者の記憶力を悪化させると報告された。

Dement Geriatr Cogn Disord. 2008;26(1):50-7. doi: 10.1159/000141484. Epub 2008 Jun 27.

High tofu intake is associated with worse memory in elderly Indonesian men and women.

Hogervorst E¹, Sadjimim T, Yesufu A, Kreager P, Rahardjo TB.

Abstract

BACKGROUND/AIMS:

Cell culture studies suggest that phytoestrogens, abundant in soy products such as tempe and tofu, could protect against cognitive decline. Paradoxically, the Honolulu Asia Aging Study reported an increased risk for cognitive impairment and other dementia markers with high tofu (soybean curd) intake.

METHODS:

A cross-sectional study was carried out in 2 rural sites (Borobudur and Sumedang) and 1 urban site (Jakarta) among mainly Javanese and Sundanese elderly (n = 719, 52-98 years of age). Memory was measured using a word learning test sensitive to dementia and soy consumption was assessed using Food Frequency Questionnaire items.

RESULTS:

High tofu consumption was associated with worse memory (beta = -0.18, p < 0.01, 95% CI = -0.34 to -0.06), while high tempe consumption (a fermented whole soybean product) was independently related to better memory (beta = 0.12, p < 0.05, 95% CI = 0.00-0.28), particularly in participants over 68 years of age. Fruit consumption also had an independent positive association. The analyses were controlled for age, sex, education, site and intake of other foods.

CONCLUSION:

The results for tofu consumption as a risk factor for low memory function may tie in with the Honolulu Asia Aging Study data. It is unclear whether these negative associations could be attributed to potential toxins or to its phytoestrogen levels. Estrogen (through which receptors phytoestrogens can exert effects) was found to increase dementia risk in women over 65 years of age. Tempe contains high levels of phytoestrogens, but (due to fermentation) also exhibits high folate levels which may exert protective effects. Future studies should validate these findings and investigate potential mechanisms

同じ大豆食品でも、豆腐を食べると記憶力が低下するが、テンペは記憶力がアップするという結果であった。

 

この論文は、ＢＢＣニュースでも取り上げられた。

http://news.bbc.co.uk/2/hi/talking_point/7490202.stm

 

The latest study suggests phytoestrogens - in high quantity - may actually heighten the risk of dementia.

Lead researcher Professor Eef Hogervorst said previous research had linked oestrogen therapy to a doubling of dementia risk in the over-65s.

She said oestrogens - and probably phytoestrogens - tended to promote growth among cells, not necessarily a good thing in the ageing brain.

Alternatively, high doses of oestrogens might promote the damage caused to cells by particles known as free radicals.

A third theory is that damage is caused not by the tofu, but by formaldehyde, which is sometimes used in Indonesia as a preservative.

The researchers admit that more research is required to ascertain whether the same effects are found in other ethnic groups.

However, previous research has also linked high tofu consumption to an increased risk of dementia in older Japanese American men.

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2009年、インドネシアの研究結果は、認知症の本にも掲載された。

Hogervorst E, Kushandy L, Angrianni W (2009) Different forms of soy processing may determine the positive or negative impact on cognitive function of Indonesian elderly. In Hormones, Cognition and Dementia, Hogervorst E, Henderson

W, Gibbs B, Brinton RD, eds. Cambridge University Press, Edinburgh, pp. 121-132.

 

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2014年、大豆食品はアルツハイマー認知症の原因と考えられると記された。

Med Hypotheses. 2014 Mar;82(3):250-4. doi: 10.1016/j.mehy.2013.11.033. Epub 2013 Dec 7.

A possible cause of Alzheimer's dementia - industrial soy foods.

Roccisano D¹, Henneberg M², Saniotis A²

Abstract

Alzheimer's data indicate that at present, approximately one new case of this form of dementia is identified in the USA every 68 s and that by 2050 the incidence will be about every 33 s, with projections from the Alzheimer Association (USA) indicating that nearly 25% of Americans will be affected by Alzheimer's dementia by 2031. Despite the numerous advances in medical science and neurological research, the causes are still unknown and the incidence is not decreasing or levelling out. Most research on the causes of Alzheimer's dementia indicates the possible roles of viruses, obesity, physical inactivity, diabetes, psychological depression, high blood pressure, frequent inflammation, environmental or domestic chemicals and toxins, or inescapable genetic factors. Alzheimer's, being the degeneration of parts of the neural pathways in the brain, may indeed involve neuro-toxic compounds that can bypass the blood-brain barrier. Therefore, it is necessary to examine what is prolific in the environment and, in particular, the food supply. One of the many suggestions in the literature is the ingestion of food items derived from unfermented soybean products; the anti-thyroid, anti-nutrient, and endocrine disruption properties of soy can have a deleterious effect in many individuals. Among the many theories and different factors that may be involved in dementiae, soy consumption may be a significant contributor to Alzheimer's dementia, and it cannot be excluded as a possible contributing cause. Our hypothesis argues that consumption of soy food products may contribute to the increasing incidence of Alzheimer's dementia and other dementiae.

大豆食品の摂取はアルツハイマーや他の認知症と関係していると考えられる。

 

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2014年、英国のレビュー論文で、欧米並みの植物エストロゲンの摂取はアルツハイマー認知症の予防に有効かもしれないが、アジアのように大量に摂取している場合は、逆効果になって脳に悪影響を与える可能性があると記された。

 

Maturitas. 2014 Mar;77(3):209-20. doi: 10.1016/j.maturitas.2013.12.010. Epub 2014 Jan 8.

Phytoestrogens and cognitive function: a review.

Soni M¹, Rahardjo TB², Soekardi R², Sulistyowati Y², Lestariningsih², Yesufu-Udechuku A³, Irsan A⁴, Hogervorst E⁵.

 

Abstract

Neuroprotective effects of phytoestrogen compounds (found in soy) have been demonstrated in animal research and cell culture studies. In particular, phytoestrogens have been shown to reduce Alzheimer's Disease (AD) related pathology, potentially alleviating risk of AD progression. In addition to their antioxidant properties, soy products also have the ability to affect cognition via interaction with estrogen receptors. However, observational studies and randomised controlled trials in humans have resulted in inconclusive findings within this domain. There are several possible reasons for these discrepant data. Studies which report no effect of phytoestrogens on cognition have mainly been carried out in European cohorts, with an average low dietary consumption. In contrast, investigation of Asian populations, with a higher general intake of tofu (a non-fermented soy product) have shown negative associations with cognitive function in those over the age of 65. Consideration of type of soy product is important, as in the latter sample, protective effects of tempe (fermented soy) were also observed. Limited data provide evidence that effects of phytoestrogens on cognition may be modified by dosage, duration of consumption andcognitive test used. Additionally, characteristics of the study population including age, gender, ethnicity and menopausal status appear to be mediating variables. Phytoestrogen treatment interventions have also shown time-limited positive effects on cognition. These findings are consistent with estrogen treatment studies, where initial positive short-term cognitive effects may occur, which reverse with long-term continuous use in elderly women. Well controlled, large scale studies are needed to assess the effects of phytoestrogens on the aging brain and provide further understanding of this association.

エストロゲンでの更年期障害の治療は短期間にすべきで、長期間行うべきではない。

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2015年、中国から、豆腐の摂取量と認知症の関係が報告された。

 

J Alzheimers Dis. 2015;43(2):669-75. doi: 10.3233/JAD-141593.

Tofu intake is associated with poor cognitive performance among community-dwelling elderly in China.

Xu X¹, Xiao S², Rahardjo TB³, Hogervorst E⁴

 

Abstract

Tofu is a soy product which is commonly consumed in Asian countries, such as China and Indonesia. Several studies found negative associations of high tofu consumption with cognitive function in older Asian populations. However, the effect of tofu on cognitive function remains disputed as it was not found in Western populations. In the present study, the effect of weekly tofu intake on cognitive performance was investigated in an observational cross sectional study of 517 Chinese elderly from Shanghai. Similar to earlier studies, results showed that a higher weekly intake of tofu was associated with worse memory performance using the Hopkins Verbal Learning Test (β = -0.10, p = 0.01) after controlling for age, gender, education, being vegetarian, and weekly intake of fruit/juice, green vegetables, and orange/red vegetables. Furthermore, among older elderly (≥68 years of age), high tofu intake increased the risk of cognitive impairment indicative of dementia (OR = 1.27, 95% CI = 0.99-1.64, p = 0.04), after adjusting for all covariates. Consumption of meat and green vegetables independently also reduced risk of dementia. To conclude, high intake of tofu was negatively related to cognitive performance among community-dwelling elderly in China. Similar findings were reported in Indonesia and in Japanese Americans in the US. These findings suggest that the effect of tofu on cognition in elderly should be further investigated.

高齢者において、多量の豆腐の摂取は認知症と関係している。

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ネットでは、認知症になるトップ10食品として、水銀、ジアセチル、グルタミン酸ナトリウム、トランスアミノ酸とともに、大豆豆腐がランキングされている。

http://www.top10grocerysecrets.com/2015-07-17-top-10-ingredients-cause-dementia.html

 

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以上のように、中国やインドネシアの人が多いと思う程度に豆腐（大豆食品）を大量に食べることは、認知症となる危険があるが、少量であれば認知能力や記憶力を高める可能性もあるということである。

その理由は、イソフラボンによるエストロゲンの影響であるとされている。

確かに、更年期障害でエストロゲンを服用していると、認知症のリスクが2倍となり、特に糖尿病がある場合は認知症のリスクが14倍であると言われている。

 

 

https://www.aan.com/PressRoom/Home/PressRelease/1236

 

EMBARGOED FOR RELEASE UNTIL 4 PM ET, January 29, 2014

High Estrogen Levels, Diabetes Together May Increase Dementia Risk 14-Fold in Older Women

MINNEAPOLIS – Older women who have high estrogen levels and diabetes may have a 14 times increased risk of dementia, according to a new study published in the January 29, 2014, online issue of Neurology®, the medical journal of the American Academy of Neurology. Blood estrogens were measured in women free of dementia aged 65 or older. After a four-year follow-up, 543 women who did not have dementia were compared with 132 women who had dementia. Scientists looked at a number of risk factors for dementia, including diabetes, high blood pressure, abnormal blood clotting and other heart health risk factors. The study found that the risk of dementia more than doubled for women who had high estrogen levels after accounting for other dementia risk factors. For those who had high estrogen levels and diabetes, the risk for dementia increased dramatically, by 14 times. Estrogen levels were about 70 percent higher in women with diabetes who also had dementia compared to those without dementia. No other heart health risk factors raised the dementia risk. “These results are surprising, given the expected brain protective effects of estrogen-based therapy,” said study author Pierre-Yves Scarabin, MD, with the French National Institute of Health and Medical Research (INSERM) in Villejuif, France. “However, more and more evidence suggests an association between high estradiol levels and dementia in women who have undergone menopause. Considering the expected increase in the number of elderly people with diabetes and dementia, more research on this topic should be urgently conducted.” The research was supported by INSERM, the Victor Segalen-Bordeaux II University, Sanofi-Aventis, Foundation for Medical Research, National Health Fund for Employees, Directorate General of Health, MGEN, Institute of Longevity, Regional Councils of Aquitaine and Bourgogne, Foundation of France, and the National Agency of Research.



日本では、イソフラボンの飲用が推奨されているので、

他の国よりも、認知症になるリスクが高いのかもしれません。