Eating for Longevity
If you’ve read the blog post Diet and Lifestyle Can Reduce Biological Age you’ll know that a few dietary, lifestyle and supplement interventions can reduce biological age. The research goal of scientists in the field of longevity has shifted from the search for strategies to extend lifespan to instead looking at how to increase the years we remain healthy. This is termed the healthspan. The ageing process can be affected by dietary, lifestyle, environmental and genetic factors. There is no doubt that what we eat is a key component affecting our health. This blog post will focus on some of the dietary recommendations aimed at increasing longevity and healthspan.
Mechanisms of Longevity
Ageing is a complicated process. Mechanisms that affect longevity in humans include mTor (mammalian target of rapamycin), telomere length, cell senescence, epigenetic modifications, IGF-1, sirtuins, AMP-activated protein kinase (AMPK), oxidative damage, inflammation, glucose homeostasis, changes in the neuroendocrine systems and autophagy (1,2,3).
Dietary strategies that are being investigated to see whether they can extend healthspan include:
- Caloric restriction without malnutrition
- Intermittent fasting
- Blue Zones Diets
- Plant based diets
Before we look at these in more detail it is worth noting that avoiding obesity along with physical activity while young or middle aged promotes longevity. However, in older age being slightly overweight is associated with a longer life-span (4).
Calorie restriction has been shown to be a modulator of longevity in multiple species. Evidence suggests that sustained periods of calorie restriction without malnutrition reduces the risk of type 2 diabetes, cardiovascular diseases, cancer, and neurological disorders. However, most research is done on yeasts, nematodes, fruit flies and rodents. Longitudinal research on humans and primates is limited.
Intermittent fasting involves interspersing normal caloric intake with short periods of calorie restriction or fasting. It is found to be effective at reducing body weight, reducing insulin resistance, decreasing leptin and reducing inflammation (5,6). Examples include the 5:2 diet and intermittent protein restriction:
The 5:2 Diet – involves five days of regular eating interchanged with two days of eating fewer than 800kcal a day. Some people prefer a 6:1 approach with one day a week of restricted eating.
Protein Restriction – intermittent reductions in protein intake are associated with lower IGF-1 levels and decreases in ageing-related diseases.
Despite the potential benefits of intermittent fasting questions remain about the side effects, what role genetics, gender and the microbiome play, whether there is an optimal fasting pattern or an ideal calorie limit, and how sustainable it is.
Whichever method of fasting is chosen it’s important that fasting is interspersed with feasting in order to fully nourish the body. Even so, long term dietary restrictions may not be feasible for most people and may have unwanted detrimental effects on the thyroid, adrenal glands, sex hormones, immune system and wound healing.
Oxidative damage is one major factor in ageing. Foods that promote longevity are rich in antioxidants which reduce oxidative damage. Blood concentrations of vitamin C, carotenoids and vitamin E appear to reduce the risk of cardiovascular disease, cancer, and all-cause mortality (7). Antioxidant rich foods include fruit, vegetables, nuts, seeds, herbs and spices.
Blue Zones Diets
Research into the dietary patterns of populations with long life-spans, known as Blue Zones, find several shared features including:
- High intake of unrefined carbohydrates
- Moderate intake of protein from vegetables/legumes, fish, and lean meats
- Higher intake of mono and polyunsaturated fats including omega 3 fats and lower intake of saturated fat
- Low glycaemic load
- High in plant foods
- High in antioxidants and phytonutrients
Blue zones include the Mediterranean and the Japanese Island of Okinawa. These diets induce less inflammation and oxidative stress both of which promote healthy ageing (8).
If you want to keep things simple just aim to eat a largely plant-based diet. Research suggests that diets high in plant foods could prevent several million premature deaths each year if adopted globally. A high intake of fruits, vegetables, whole grains, and nuts is inversely associated with the risk of cardiovascular disease, cancer, and all-cause mortality (7,9).
Suggested optimal intakes are:
800g a day of fruits and vegetables
225 g a day of whole grains
15-20g a day of nuts
To find out about ageing and muscle loss read Maintain Muscle to Maintain Health.
1. Crit Rev Food Sci Nutr. 2020;60(18):3063-3082. Nutrition and longevity – From mechanisms to uncertainties. Ekmekcioglu C.
2. Ageing Res Rev. 2020 Dec;64:101038. Calorie restriction for enhanced longevity: The role of novel dietary strategies in the present obesogenic environment. Dorling JL et al.
3. Exp Suppl. 2016;107:227-256. AMPK as a Pro-longevity Target. Burkewitz K et al.
4. 2016 Jun 2;113:DYMA. The importance of food for aging and longevity. Food composition, oxidative stress and weight are important factors. Cederholm T, Hellenius M.
5. Clin Diabetes Endocrinol. 2021 Feb 3;7(1):3. Intermittent fasting: is there a role in the treatment of diabetes? A review of the literature and guide for primary care physicians. Albosta M et al.
6. Mediterr J Rheumatol. 2020 Mar 31;30(4):201-206. Fasting mimicking diets: A literature review of their impact on inflammatory arthritis. Venetsanopoulou AI et al.
7. Adv Nutr. 2019 Nov 1;10(Suppl_4):S404-S421. Plant Foods, Antioxidant Biomarkers, and the Risk of Cardiovascular Disease, Cancer, and Mortality: A Review of the Evidence. Aune D.
8. Mech Ageing Dev. Mar-Apr 2014;136-137:148-62. Healthy aging diets other than the Mediterranean: a focus on the Okinawan diet. Willcox DC et al.
9. Adv Nutr. 2016 Nov 15;7(6):1052-1065. Whole-Grain Intake and Mortality from All Causes, Cardiovascular Disease, and Cancer: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies. Benisi-Kohansal S. et al.