In one of our earlier post regarding Okinawans and their exceptional long centenarian lives, it drew many researchers to deep-dive into varying factors that prolonged their health & lifespan. One common misunderstanding often conveniently points health longevity to solely genetics, as we all commonly coin the use of “fate” with many uncontrollable aspects of our lives. True enough, there are instances that no matter how cautious we get, we can only reduce the underlying risks. Why do diseases still befall on the health-conscious pedantics? Why are there children who go through aggressive cancers at such a young age? Interestingly, there’s a world of science out there relating to genetic expressions through lifestyle, behavioural and social factors. Today, we focus on diet and nutrients as modulators in addition to traditional genetic mechanisms.

Nutrients as Epigenetic Modulators of Health Span

In a study published by Bell & Spector (2011), it was found that genetics at birth determines only about 25% of our life span. As such, epigenetic factors such as diet and nutrients intake forms the majority of their influence on health span. Naturally, environmental and lifestyle factors will play key roles in modulating health. Ekmekcioglu (2019) particularly highlighted a conclusive major benefit coming from nutrition components and diet, that give strong evidences in association to health extension. They are supported by the following factors:

• Calories restriction without malnutrition 
• Methionine restriction (MetR); Sulphur-containing amino acid that is required for cellular function, however may have adverse effects in the long-term
• Lower protein intake 

MetR in possible relations to certain diet lower in protein-intake that enhances antioxidative defense, lowers oxidative stress and ultimately increasing health span but lowering risks of metabolic diseases and cancer growth (Kitada et al., 2021)

The spotlight focus here highlights the impact of high protein intake in relation to longevity. Traditionally where diet selection is involved, we are often inclined to the knowledge of higher protein intake, low carbs for glucose control, with a balance of fruits and vegetables. However, Babygirijia & Lamming (2021) have shown that protein restriction, with the emphasis on animal protein, has shown positive association to health span longevity. This is due to the restriction of methionine which is beneficial to metabolic health and antioxidative defense as shown in the figure above. Regardless of an Okinawan diet or a Mediterranean diet, the foundation of longevity diet hinges on the following:

• Low in animal protein; no red or processed meat
• High in complex carbohydrates such as whole grains, legumes; refined carbs and sugar constitute simple carbs
• Calories restriction; adopting the idea of 80% full
• 30% of calories from vegetable fats such as nuts and olive oil

Taken from Babygirijia & Lamming (2021), a graphical summary of benefits from incorporating protein restriction into our diet

It is thus important to understand the nutrition requirement and breakdown rather than to chase a particular diet when considering health span longevity. Ketogenic, vegan, pescaterian, Mediterranean diets? These are just categorised subsets of nutrients that make up the majority of calories intake by an individual. There are multiple ways to eat and we do not have to conform to a particular diet restriction, especially one that affects our mental well-being and development of eating disorders in the long run. Let us analyse 2 particular diets where the most centenarians consume, observing 2 distinctly separate regions of the world – Okinawa of Japan, Icaria of Greece.

	Okinawan Diet (OD)	Mediterranean Diet (MD)
Majority of Calories	Complex carbs; Traditionally 9:1 ratio carbs vs protein	Complex carbs takes up most of diet calories, with some refine (simple) carbs
Focuses on	Sweet potatoes, seaweed, kelp, bamboo shoots, daikon radish, cabbage, carrots, Chinese okra, pumpkin, green papaya, millets, rice, wheat, noodles	Vegetables – (Tomatoes, kale, spinach, broccoli, brussel sprouts, cucumbers), fruits, nuts, seeds, legumes, potatoes, whole grain, herbs, spices, seafood, extra virgin olive oil
Low to moderate consumption	Tofu, natto, edamame, miso	Poultry, eggs, cheese, yogurt, red wine
Limit intake	White fish, seafood, pork (all cuts including organs)	Red meat, sugar beverages, processed meats, refined grains, beers, liquors

Similarities and Key Findings

1. Both OD and MD are high in carbs. Made up of mainly complex carbs, both diets avoid refined sugar. MD differs through higher consumption for whole grains, bread and pasta.

1. OD and MD places a lot of focus on vegetables and fruits. These give abundance in vitamins, minerals and antioxidants while meeting calories requirements. 

1. Though low in protein intake, both OD and MD focuses on white meats as opposed to red and processed meats. 

1. OD hinges on the principle of Hara hachi bu – “eating till you are 80% full”. The idea of eating till “satisfactory” as opposed to feeling full after a meal. However, both OD and MD do not enforce strict adherence to calories counting.

From the above comparison, both diets conform to similar nutrition intake mix although they are made up of very different ingredients. While both diets highlight the abundance of fruits and vegetables, it is not considered vegetarian or vegan diets as there are still allowances of white meat animal and fish protein, poultry and dairy products. It is however advocated on 2 separate studies, Babygirija & Lamming (2021) and Pignatti et al. (2020), that plant-based protein is preferred as a better protein quality. Animal proteins are found to contain higher amount of tryptophan, methionine and leucine levels – associated with high all-cause mortality, cardiovascular and cancer mortality. However, the rule of thumb surrounds limit intake and eating in moderation. Adhering to the guidelines of longevity diet, doesn’t restrict against consumption of animal protein. Plant-based protein commonly includes the following:

• Nuts
• Chickpeas
• Soy & legumes
• Quinoa
• Lentils
• Nutritional yeast
• Seeds
• Brown rice
• Tofu
• Oats
• Broccoli

What about fat intake?

Consequently with the intake of excessive animal protein, comes along with saturated fat present in most animal source. Not all types of fat sources are made equal. In a bid to getting the “Fats” right, they are typically broken down into the following:

• Trans fat – Coming from hydrogenated oils, these are fats that are found in deep fried foods, pastries, cakes, cookies, and biscuits. Trans fat raises LDL-C and lowers HDL-C, which is detrimental to our health with increased risk of cardiovascular diseases and all-causes mortality.

• Saturated fat – It is often perceived and grouped along with trans fat as “bad” fats. Interestingly, there are growing number of studies that have shown that saturated fat can be limited and eaten in moderation. Not to be confused with trans-fat, saturated fat can also be found in nutrients-rich diets such as dairy and poultry. 

Taken from “The Nutrition Source” (2016), Harvard T.H. Chan, adapted from Wang et al., JAMA Intern Med, 2016. (Source: https://nutritionsource.hsph.harvard.edu/2016/07/05/different-dietary-fat-different-risk-of-mortality/)

• Monounsaturated fat – Found largely in the Mediterranean diet such as olive oil, nuts, and avocados. Monounsaturated fat helps to lower LDL-C. 

• Polyunsaturated fat – Commonly broken down into 2 major chains, omega-3 and omega-6 polyunsaturated fatty acids (PUFAs). These are essential fats required by our bodies, which must be included in our diets. Not only do they reduce bad cholesterol and triglycerides, they are also essential for cellular functions and other benefits such as inflammation management in chronic diseases (Kiecolt-Glaser, 2011).

Drawing the diet composition from both OD and MD, both promotes the consumption of unsaturated fats in which we may draw relevance to their health benefits for health span longevity. In fact when considering fat composition in MD, it has relatively high intake of approximately 25-35% of daily calories made up of mostly extra virgin olive oil, nuts, and seeds (Tosti et al., 2018). Yet, the majority of it made up of unsaturated fats with very little trans or saturated fats, yielded great health benefits through abundance of omega-3 and omega-6 PUFAs along with plant sterols. 

Key Takeaways

Longevity diet comprises of the following.

• Carbs make up the majority of calorie contribution with complex carbs as the majority, while avoiding processed foods and refined sugar.

• Lower animal protein intake and limit to white meat. Plant protein (such as soy, tofu, nuts) is preferred as a higher quality protein.

• Calories restriction is beneficial, however it is more important that essential nutrients are all met. This can be achieved through consumption of fruits, vegetables, nuts, legumes.

• PUFAs such as omega-3 and 6 are essential fats that should be incorporated into our diets. Trans fat to be avoided, and saturated fat to be limited in moderation (typically through the consumption of dairy products and poultry).

*These findings do not constitute to professional medical or nutritional health planning advice. This article is written for knowledge and nutrition awareness. Please seek professional advice for any healthcare related conditions.*

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References

Bell JT, Spector TD. A twin approach to unraveling epigenetics. Trends Genet. 2011 Mar;27(3):116-25. doi: 10.1016/j.tig.2010.12.005. Epub 2011 Jan 21. PMID: 21257220; PMCID: PMC3063335.

Ekmekcioglu C. Nutrition and longevity – From mechanisms to uncertainties. Crit Rev Food Sci Nutr. 2020;60(18):3063-3082. doi: 10.1080/10408398.2019.1676698. Epub 2019 Oct 21. PMID: 31631676.

Kitada M, Ogura Y, Monno I, Xu J, Koya D. Effect of Methionine Restriction on Aging: Its Relationship to Oxidative Stress. Biomedicines. 2021 Jan 29;9(2):130. doi: 10.3390/biomedicines9020130. PMID: 33572965; PMCID: PMC7911310.

Babygirija R, Lamming DW. The regulation of healthspan and lifespan by dietary amino acids. Transl Med Aging. 2021;5:17-30. doi: 10.1016/j.tma.2021.05.001. Epub 2021 May 24. PMID: 34263088; PMCID: PMC8277109.

Pignatti C, D’Adamo S, Stefanelli C, Flamigni F, Cetrullo S. Nutrients and Pathways that Regulate Health Span and Life Span. Geriatrics (Basel). 2020 Nov 19;5(4):95. doi: 10.3390/geriatrics5040095. PMID: 33228041; PMCID: PMC7709628. 

Kiecolt-Glaser JK, Belury MA, Andridge R, Malarkey WB, Glaser R. Omega-3 supplementation lowers inflammation and anxiety in medical students: a randomized controlled trial. Brain Behav Immun. 2011 Nov;25(8):1725-34. doi: 10.1016/j.bbi.2011.07.229. Epub 2011 Jul 19. PMID: 21784145; PMCID: PMC3191260.

Tosti V, Bertozzi B, Fontana L. Health Benefits of the Mediterranean Diet: Metabolic and Molecular Mechanisms. J Gerontol A Biol Sci Med Sci. 2018 Mar 2;73(3):318-326. doi: 10.1093/gerona/glx227. PMID: 29244059; PMCID: PMC7190876.