Legumes: The Most Important Dietary Predictor Of Survival In Older People Of Different Ethnicities

Abstract

To identify protective dietary predictors amongst long-lived elderly people (N=785), the “Food Habits in Later Life” (FHILL) study was undertaken among five cohorts in Japan, Sweden, Greece and Australia. Between 1988 and 1991, baseline data on food intakes were collected. There were 785 participants aged 70 and over that were followed up to seven years. Based on an alternative Cox Proportional Hazard model adjusted to age at enrolment (in 5-year intervals), gender and smoking, the legume food group showed 7-8% reduction in mortality hazard ratio for every 20g increase in daily intake with or without controlling for ethnicity (RR 0.92; 95% CI 0.85-0.99 and RR 0.93; 95% CI 0.87-0.99, respectively). Other food groups were not found to be consistently significant in predicting survival amongst the FHILL cohorts.

Generated Summary

The study, titled “Legumes: the most important dietary predictor of survival in older people of different ethnicities”, investigated the correlation between food intake and survival among elderly individuals of diverse ethnicities. The research employed a cross-cultural study design, drawing on data from the “Food Habits in Later Life” (FHILL) study, which included cohorts from Japan, Sweden, Greece, and Australia. The study’s primary methodology involved analyzing baseline food intake data collected between 1988 and 1991 and correlating it with mortality data over a seven-year follow-up period. Researchers utilized the Cox Proportional Hazard model to assess the impact of various food groups on mortality, adjusting for factors such as age, gender, smoking status, and ethnicity. The research aimed to identify protective dietary predictors and understand how different food cultures impact longevity. The central focus was on the role of legumes and other dietary factors in influencing survival rates within and between the diverse cohorts. The study compared average food consumption and individual food groups as predictors of mortality, providing cross-cultural comparisons to understand the impact of diet on longevity across diverse ethnic backgrounds.

Key Findings & Statistics

• The study included 785 participants aged 70 and over.
• 169 people died during the follow-up period.
• Legumes intake showed a 7-8% reduction in mortality hazard ratio for every 20g increase in daily intake, with or without controlling for ethnicity (RR 0.92; 95% CI 0.85-0.99 and RR 0.93; 95% CI 0.87-0.99, respectively).
• Higher intakes of legumes, fish and shellfish, and olive oil were significant predictors of survival.
• Vegetable consumption varied, with most cohorts consuming between 283 and 353 g/d, but Swedes consumed less.
• The Japanese in Japan, along with both Greek cohorts, consumed more legumes (63-86g/d) compared to other cohorts.
• Fruit and nut intakes were low for the Japanese in Japan (140g/d) compared to the rest of the cohorts (252-330g/d).
• Cereals consumption was high for the Japanese in Japan (366g/d).
• Milk and dairy consumption varied between cohorts, with Swedes consuming more than 400g/d, while Japanese consumed 165g/d.
• Meat consumption varied greatly. The Japanese ate very little meat (less than 50g/d), while Greeks in Australia ate about 190g of meat daily.
• The Anglo-Celts in Australia consumed little fish and shellfish (21g/d), while the Japanese consumed more than 100g daily.
• Japanese reported a low energy intake (about 1600 kcal daily), while Swedes consumed about 2500 kcal daily.
• For every 20 grams increase in legumes intake, there was a 7%-8% reduction in risk of death.
• For every 20 grams increase in fish and shellfish intake, there was a 6% decrease in the hazard of death (95% CI 1%-12%).
• For every unit increase in the mono-unsaturated:saturated fat ratio, there was a 46% decrease in the hazard of death (95% CI 9%-68%).

Other Important Findings

• The study compared the average amount of food consumed per person daily among FHILL cohorts.
• The Japanese in Japan consumed more cereals than other groups.
• The Japanese consumed significantly more fish and shellfish than the Anglo-Celts.
• Ethanol consumption varied across cohorts, with Japanese men consuming more than other groups.
• Higher intakes of legumes, fish and shellfish, and olive oil were significant predictors of survival in the elderly.
• The study compared results to the “Seven Countries Study,” noting differences in cereal, meat, and alcohol consumption.
• The Mediterranean diet, characterized by plentiful fruits, vegetables, legumes, grains, olive oil, lean red meat, moderate dairy, and moderate wine consumption, has been linked to longevity.
• The monounsaturated:saturated fat ratio was a significant predictor of mortality only when ethnic background was included.

Limitations Noted in the Document

• The study relies on self-reported food intake data through FFQs and 3-day food records, which may be subject to recall bias and inaccuracies.
• The study’s observational nature means that it cannot establish causation, only correlation.
• The study’s findings are based on cohorts from specific geographic locations (Japan, Sweden, Greece, and Australia), limiting generalizability to other populations.
• The analysis is adjusted for some confounding factors, such as age, gender, and smoking status, but other unmeasured factors could influence the results.
• The reliance on a Cox Proportional Hazard model assumes proportional hazards, which may not always be valid.
• The study does not account for the preparation methods of foods, which can impact health outcomes.
• The Mediterranean diet is a complex dietary pattern, making it difficult to isolate the effects of individual components.

Conclusion

The FHILL longitudinal study highlights the protective role of a higher legume intake as a dietary predictor of survival among the elderly, irrespective of ethnicity. The study’s findings underscore the importance of dietary patterns in influencing longevity, particularly the role of legumes, fish and shellfish intake, and the ratio of monounsaturated to saturated fats. The consistent significance of legumes in predicting survival suggests the potential benefits of incorporating legumes into the diets of older adults across diverse cultural backgrounds. The study emphasizes that while there were differences in food consumption patterns among the cohorts, the overall trends support the value of plant-based diets. The study notes that the average cereal and ethanol consumption were lower, and the average meat consumption was higher, in comparison to the “Seven Countries study” in the 1960s. The study’s comparison of dietary patterns across the cohorts found that the Japanese consumed more vegetables, fruits, meat, and dairy products than the Japanese cohort from the “Seven Countries Study”. The study notes that only for legumes intake was the result plausible, consistent and statistically significant. The study suggests that the positive outcomes are connected to the high consumption of legumes. As the study shows, there is a 7%-8% reduction in risk of death for every 20 grams increase in daily legumes intake. The study’s findings highlight the importance of food intake as a crucial element in promoting health and longevity, emphasizing the role of dietary choices in improving health outcomes, especially in older populations. The study reinforces the notion that adopting dietary patterns rich in legumes, and similar to the traditional Mediterranean diet, may contribute to improved health and longevity.