ADAPTING DIET AND LIFESTYLE TO INCREASE LONGEVITY AND EXTEND HEALTHY YEARS

Data from the World Health Organization (WHO) show that the average life expectancy on a global level increased by 5.5 years between 2000 and 2016, accounting for the fastest increase since the 1960s. By 2050, one in 4 persons living in Europe and North America could be aged 65 or over, based on United Nations’ (UN) reports.

As we age, we are more susceptible to develop chronic diseases and disability. The trend toward increased longevity has not been followed with an increase in disease-free years, which suggests that people live longer but have reduced quality of life, due to more years with illness and disability.¹ Also, living longer but in deteriorated health could result in increased demand on public health resources, and therefore can be a financial burden to societies.² Consequently, over the past decade considerable effort was aimed at identifying and understanding lifestyle behaviors associated with a healthier aging process.³

Determinants of Longevity  

Our research team at the Institute of Social and Preventive Medicine, University of Bern categorizes the determinants of human longevity as those attributed to sex (accounting for differences in anatomy, reproductive functions, sex steroid hormones, gene expression) and gender (factors related to health behavior, social participation, and lifestyle).⁴ Traditionally it was believed that men live shorter but healthier lives, whereas women live longer but less healthy lives.⁵ However, this assumption is not entirely true as the differences observed depend on social circumstances and behaviors that vary among countries.⁶

Recent U.S. research found that adherence to a healthy lifestyle at midlife is associated with increased life expectancy free of major chronic diseases.⁷ Another U.S. study estimated that adherence to 5 low-risk, lifestyle-related factors (never smoking, normal body weight, 30 or more min/day of moderate to vigorous physical activity, moderate alcohol intake, and a high diet quality score) could prolong life expectancy at age 50 years by 14.0 and 12.2 years for female and male adults, respectively.⁸ Among these 5 physical factors, exercise and healthy dietary patterns appear to be the most effective at promoting health. However, due to physical limitations or other obstacles to exercise,⁹ dietary changes may be a more practical target for chronic disease prevention.

Desirable Dietary Behavior

Nutrition plays an important role in healthy aging. Healthy dietary patterns have been associated with improved cardiometabolic health and decreased risk of cancer and mortality.^10-12 Current U.S. dietary guidelines recommend a diet rich in fruits, vegetables, whole grains, low-fat dairy, poultry, fish, and legumes, yet a large number of individuals do not adhere to these recommendations.

Evidence indicates that plant-based dietary patterns are associated with reductions in risk of obesity, hypertension, and diabetes.^13,14 Cruciferous vegetables and whole grain cereals are linked with better health outcomes that may be attributed to their high fiber content, such as β-glucan, essential fatty acids, vitamins, and antioxidant phytochemicals, including select phenolic compounds.^15-17

Popular weight loss strategies include restricting carbohydrate intake in favor of increased protein or fat.¹⁸ However, people on low-carbohydrate diets tend to eat fewer vegetables and fruits - which are rich in micronutrients and fiber - and more animal-derived foods.¹⁸   Furthermore, low carbohydrate dietary patterns favoring animal-derived protein and fat sources (from lamb, beef, pork, and chicken) were associated with higher mortality, while those that favored plant-derived protein and fat intake (from vegetables, nuts, peanut butter, and whole grain breads) were associated with lower mortality, suggesting that the source of food notably modifies the association between carbohydrate intake and mortality.^18,19

Among the various sources of plant protein, soy has become quite popular and has been linked with various health benefits including a lower risk of dying due to all causes, cancer, and cardiovascular disease.^19,20 Soyfoods are an abundant source of phytoestrogens, plant-derived polyphenols with estrogen-like biological activity. Phytoestrogens have been linked with improvement in menopausal symptoms²¹ and a decrease in diabetes risk in women.²²

Evidence has shown that overall “diet quality” may be a more reliable index for healthy nutrition than “nutrient quantity” or the source of individual nutrients.²³  That is, the focus should be on the overall dietary pattern, not on specific sources of macro- or micronutrients.  For example, the Dietary Approaches to Stop Hypertension (DASH) diet, which promotes consumption of vegetables, fruits, and low-fat dairy products, as well as moderate sodium intake, has been linked to lower risk of developing chronic diseases.²⁴ In addition, the 2015-2020 Dietary Guidelines for Americans specifies that consumers can choose among several healthy dietary patterns including Healthy U.S.-Style, Mediterranean-Style and vegetarian to achieve diet quality.²⁵ 

Future Perspectives

A group of researchers recently projected global dietary patterns in 2050. They concluded that in comparison to current dietary patterns, our future diets may contain fewer servings of fruits and vegetables, about 60% more empty calories (calories from refined fats, refined sugars, alcohols, and oils), and 25-50% more pork, poultry, beef, dairy, and eggs.²⁶ According to the study, these dietary trends may contribute to lower global life expectancies. Alternatively, consuming more fruits, vegetables, whole grains, low-fat dairy, poultry, fish, and legumes could help prevent diet-related chronic non-communicable diseases.²⁵

Increasing interest in plant-based eating patterns raises the opportunity for developing novel preventive and therapeutic strategies against obesity and related comorbidities. Still, putative effects of plant-based diets on the number of years of life spent free of chronic disease remains largely unexplored. Future research is needed to address their impact.

References

1.  DALYs GBD, Collaborators H, Murray CJ, et al. Global, regional, and national disability-adjusted life years (DALYs) for 306 diseases and injuries and healthy life expectancy (HALE) for 188 countries, 1990-2013: quantifying the epidemiological transition. Lancet 2015;386(10009):2145-91. doi: 10.1016/S0140-6736(15)61340-X [published Online First: 2015/09/01]
2. Prina AM. Ageing, resilience and depression: adding life to years as well as years to life. Epidemiol Psychiatr Sci 2017;26(6):571-73. doi: 10.1017/S2045796017000282 [published Online First: 2017/07/01]
3. Lowsky DJ, Olshansky SJ, Bhattacharya J, et al. Heterogeneity in healthy aging. J Gerontol A Biol Sci Med Sci 2014;69(6):640-9. doi: 10.1093/gerona/glt162 [published Online First: 2013/11/20]
4. Ostan R, Monti D, Gueresi P, et al. Gender, aging and longevity in humans: an update of an intriguing/neglected scenario paving the way to a gender-specific medicine. Clin Sci (Lond) 2016;130(19):1711-25. doi: 10.1042/CS20160004 [published Online First: 2016/08/25]
5. Austad SN. Why women live longer than men: sex differences in longevity. Gend Med 2006;3(2):79-92. doi: 10.1016/s1550-8579(06)80198-1 [published Online First: 2006/07/25]
6. Crimmins EM, Shim H, Zhang YS, et al. Differences between Men and Women in Mortality and the Health Dimensions of the Morbidity Process. Clin Chem 2019;65(1):135-45. doi: 10.1373/clinchem.2018.288332 [published Online First: 2018/11/28]
7. Li Y, Schoufour J, Wang DD, et al. Healthy lifestyle and life expectancy free of cancer, cardiovascular disease, and type 2 diabetes: prospective cohort study. BMJ 2020;368:l6669. doi: 10.1136/bmj.l6669 [published Online First: 2020/01/10]
8. Li Y, Pan A, Wang DD, et al. Impact of Healthy Lifestyle Factors on Life Expectancies in the US Population. Circulation 2018;138(4):345-55. doi: 10.1161/CIRCULATIONAHA.117.032047 [published Online First: 2018/05/02]
9. Baert V, Gorus E, Mets T, et al. Motivators and barriers for physical activity in older adults with osteoporosis. J Geriatr Phys Ther 2015;38(3):105-14. doi: 10.1519/JPT.0000000000000035 [published Online First: 2015/01/17]
10. Kraja B, Muka T, Ruiter R, et al. Dietary Fiber Intake Modifies the Positive Association between n-3 PUFA Intake and Colorectal Cancer Risk in a Caucasian Population. J Nutr 2015;145(8):1709-16. doi: 10.3945/jn.114.208462 [published Online First: 2015/06/05]
11. Te Morenga LA, Howatson AJ, Jones RM, et al. Dietary sugars and cardiometabolic risk: systematic review and meta-analyses of randomized controlled trials of the effects on blood pressure and lipids. Am J Clin Nutr 2014;100(1):65-79. doi: 10.3945/ajcn.113.081521 [published Online First: 2014/05/09]
12. Chen Z, Glisic M, Song M, et al. Dietary protein intake and all-cause and cause-specific mortality: results from the Rotterdam Study and a meta-analysis of prospective cohort studies. Eur J Epidemiol 2020 doi: 10.1007/s10654-020-00607-6 [published Online First: 2020/02/23]
13. Tonstad S, Butler T, Yan R, et al. Type of vegetarian diet, body weight, and prevalence of type 2 diabetes. Diabetes Care 2009;32(5):791-6. doi: 10.2337/dc08-1886 [published Online First: 2009/04/09]
14. Yokoyama Y, Barnard ND, Levin SM, et al. Vegetarian diets and glycemic control in diabetes: a systematic review and meta-analysis. Cardiovasc Diagn Ther 2014;4(5):373-82. doi: 10.3978/j.issn.2223-3652.2014.10.04 [published Online First: 2014/11/22]
15. Gangopadhyay N, Hossain MB, Rai DK, et al. A Review of Extraction and Analysis of Bioactives in Oat and Barley and Scope for Use of Novel Food Processing Technologies. Molecules 2015;20(6):10884-909. doi: 10.3390/molecules200610884 [published Online First: 2015/06/16]
16. Flander L S-MM, Suortti T, Autio K Optimization of ingredients and baking process for improved wholemeal oat bread quality. . LWT- Food Sci Technol 40:860–870 2007
17. Kapusta-Duch J, Kopeć A, Piątkowska E, et al. The beneficial effects of Brassica vegetables on human health. Roczniki Państwowego Zakładu Higieny 2012;63:389-95.
18. Shai I, Schwarzfuchs D, Henkin Y, et al. Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. N Engl J Med 2008;359(3):229-41. doi: 10.1056/NEJMoa0708681 [published Online First: 2008/07/19]
19. Yan Z, Zhang X, Li C, et al. Association between consumption of soy and risk of cardiovascular disease: A meta-analysis of observational studies. Eur J Prev Cardiol 2017;24(7):735-47. doi: 10.1177/2047487316686441 [published Online First: 2017/01/10]
20. Nachvak SM, Moradi S, Anjom-Shoae J, et al. Soy, Soy Isoflavones, and Protein Intake in Relation to Mortality from All Causes, Cancers, and Cardiovascular Diseases: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies. J Acad Nutr Diet 2019;119(9):1483-500 e17. doi: 10.1016/j.jand.2019.04.011 [published Online First: 2019/07/07]
21. Franco OH, Chowdhury R, Troup J, et al. Use of Plant-Based Therapies and Menopausal Symptoms: A Systematic Review and Meta-analysis. JAMA 2016;315(23):2554-63. doi: 10.1001/jama.2016.8012 [published Online First: 2016/06/22]
22. Glisic M, Kastrati N, Gonzalez-Jaramillo V, et al. Associations between Phytoestrogens, Glucose Homeostasis, and Risk of Diabetes in Women: A Systematic Review and Meta-Analysis. Adv Nutr 2018;9(6):726-40. doi: 10.1093/advances/nmy048 [published Online First: 2018/11/22]
23. Echouffo-Tcheugui JB, Ahima RS. Does diet quality or nutrient quantity contribute more to health? J Clin Invest 2019;129(10):3969-70. doi: 10.1172/JCI131449 [published Online First: 2019/08/27]
24. Schulze MB, Martinez-Gonzalez MA, Fung TT, et al. Food based dietary patterns and chronic disease prevention. BMJ 2018;361:k2396. doi: 10.1136/bmj.k2396 [published Online First: 2018/06/15]
25. U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015–2020 Dietary Guidelines for Americans. 8th Edition. December 2015. Available at http://health.gov/dietaryguidelines/2015/guidelines/.
26. Tilman D, Clark M. Global diets link environmental sustainability and human health. Nature 2014;515(7528):518-22. doi: 10.1038/nature13959 [published Online First: 2014/11/11]