Japan has nearly 100,000 centenarians: 5 lessons from their diet for Kenyans

While observing their annual 'Respect for the Aged Day' in September 2025, Japan’s Ministry of Health, Labour and Welfare announced a new record: the nation is home to 99,763 individuals aged 100 or older.

This figure represents the highest concentration of centenarians globally and underscores a national average life expectancy of approximately 84.6 years, one of the world's highest.

In contrast, Kenya's average life expectancy is approximately 62 years.

While genetics, socioeconomic factors, and healthcare systems play significant roles, the traditional Japanese diet is consistently identified by nutritionists and epidemiologists as a primary driver of this remarkable longevity.

An examination of its core principles reveals practical lessons for improving health outcomes in Kenya using local foods and resources.

Here are five dietary principles from Japan that can be adapted for the Kenyan context.

The traditional Japanese diet features a high intake of fish and seafood, consumed several times a week.

Oily fish like mackerel, sardines, and salmon are particularly prized for their high concentration of omega-3 fatty acids.

Scientific research consistently links these fatty acids to reduced inflammation, improved cardiovascular health by lowering blood pressure and triglycerides, and enhanced brain function.

Kenya has abundant sources of high-quality marine protein.

Omena (Silver Cyprinid) is an excellent and affordable source of omega-3s and calcium.

Tilapia, widely farmed and available, is a lean protein source.

For those along the coast or in urban centres, fish like mackerel and tuna are also accessible.

Fermented foods are a cornerstone of daily Japanese meals.

Items such as miso (fermented soybean paste), natto (fermented soybeans), and soy sauce are rich in probiotics.

These beneficial bacteria are crucial for maintaining a healthy gut microbiome, which is linked to improved digestion, a stronger immune system, and even mental wellbeing.

Kenya has its own rich traditions of fermentation.

Maziwa lala (fermented milk) and traditional yoghurts are potent sources of probiotics.

Mursik, the fermented milk of the Kalenjin community, is another example.

Fermented porridge (uji) is also a common breakfast food that supports gut health.

Integrating these traditional, unprocessed fermented foods into the daily diet is a direct way to apply this principle of gut nourishment.

A typical Japanese meal is based on rice, but it is accompanied by a wide variety of vegetables, seaweed, and legumes.

They consume an average of 14 different types of vegetables daily.

Seaweed, a staple, is dense in minerals like iodine, iron, and calcium.

Root vegetables like daikon radish and sweet potatoes provide complex carbohydrates and fibre.

This plant diversity ensures a broad spectrum of vitamins, minerals, and phytonutrients into the Japanese diet.

Green tea, particularly varieties like sencha and matcha, is the most commonly consumed beverage in Japan.

It is typically served unsweetened.

Green tea is rich in antioxidants called catechins, most notably epigallocatechin gallate (EGCG).

Research indicates that EGCG has potent anti-inflammatory properties and may contribute to a lower risk of chronic diseases, including certain cancers and heart disease.

As one of the world's largest producers of tea, high-quality green tea is readily available and affordable in Kenya.

The lesson is to shift beverage habits.

Replacing sugary, milky chai or processed juices with plainly brewed green tea significantly reduces sugar intake while increasing antioxidant consumption.

This simple swap has a direct impact on daily caloric load and metabolic health.

This is a cultural practice as much as a dietary one.

The Okinawan concept of Hara Hachi Bu advises eating only until one is 80 percent full.

This practice of mindful eating prevents overconsumption and promotes a healthy body weight.

Meals are often served on smaller plates with multiple small dishes, which encourages slower eating and better recognition of satiety signals from the brain.

This principle directly challenges the culture of eating large portions until feeling completely full, particularly with calorie-dense staples.

Adopting this practice requires a conscious mental shift.

It involves paying closer attention to the body's hunger and fullness cues rather than eating out of habit.

Using smaller plates and taking time to chew food properly can help in recalibrating the sense of what constitutes a satisfying portion, thereby aiding in long-term weight management and reducing the risk of obesity-related conditions like type 2 diabetes and hypertension.

Japan's longevity is the result of a complex interplay of lifestyle factors, but diet is a powerful and modifiable component.

The core principles revolve around prioritising whole foods, embracing nutrient-dense local produce, and practising mindful consumption.

By applying these lessons through the lens of Kenya's own rich agricultural and culinary heritage, it is possible to make significant strides in public health and individual wellbeing.