CamFest Speaker Spotlight: Dr Mark Cortnage

In their event, Longevity and nutrition: can we all really live to 100 and beyond? (16 March), Professor Justin Roberts and Dr Mark Cortnage from Anglia Ruskin University, delve deeper into the secrets of the Blue Zones diet, and lessons from the oldest people on Earth. They critique the feasibility of reaching a century and whether simple nutrition and lifestyle changes can really increase our life expectancy.  

What is the Blue Zones diet and how does it work?
The Blue Zones diet is based on the observed eating habits of some of the world's longest-lived people. These geographical areas have been assigned the term ‘Blue Zones’. 

This diet emphasises a plant-centric approach, focusing on consuming a variety of fruits, vegetables, grains, nuts, and legumes. Although meat is consumed, it is eaten sparingly. Furthermore, the diet prioritises whole, unprocessed foods and healthy fats from sources such as olive oil, avocados, Okinawan imo (purple sweet potatoes) dependant on the region. Processed foods, added sugars, and unhealthy fats are minimised.  

The diet also encourages eating smaller portions (or at least to a point of not being completely full), a more intuitive approach to eating. There is a focus on regular hydration and a moderate consumption of beverages such as coffee, tea, and red wine. However, the Blue Zones diet is part of a broader lifestyle that includes physical activity, strong social ties, and a sense of purpose, all contributing to longevity and a lower risk of chronic diseases in these observed populations. 

Can it really help people live longer?
Whilst the concept of the Blue Zones diet might appear to be a useful concept, the ‘diet’ could have several imitations, for example a warmer climate being a common theme. We are aware of the psychological and physiological benefits afforded by exposure to the sun, in particular regular warmth and vitamin D levels. We also need to consider the effectiveness of each zone’s respective health care service. Access to high-quality, affordable health care has strong, positive associations with longevity.  

However, the most important aspect, and one we touch on in our talk is the quality of life. Would we rather live longer with extended periods of poor health or live to our designated time of death in good health, free from disability? Should we consider longevity more as a focus on risk reduction, positive and sustained lifestyle choices, and extended good health rather than extended life? 

What’s the science behind it? 
The research behind the Blue Zones likely stems from the AKEA study in Sardinia through observational evaluation of centenarian prevalence in specific locations compared to the wider population. Such observations were clearly inspirational in that they raised questions around longevity and put these questions into the mainstream. Longevity is a complex area to investigate, and as such, more research has been conducted around the topic ranging from assessment of genetics, lifestyle trends, to dietary interventions (most recently popularised through fasting-mimicking approaches). However, there are some challenges to the current research which could impact on whether true Blue Zones exist.

For instance, whereas many of the blue zone regions appear to be rural or remote in nature, there are other locations such as New York and Hong Kong where centenarian prevalence is also quite high, which brings into focus a need to investigate as to whether we can divide the global population into ‘zones’ that have the capacity to improve longevity. This implies that adopting an active, healthier lifestyle, no matter where you are placed geographically will potentially enhance health through a decrease in health-related risk.

For instance, the initial blue zones research led to 9 (The power 9) recommendations for improved longevity but as I touched on earlier, there are additional influences that need to be considered that were not outlined in the original research. There are several other facets that contribute to longevity and ‘muddy’ the waters. For instance, Okinawa (a designated Blue Zone) has witnessed a decline in longevity more recently, likely with most ‘Westernised’ approaches being introduced. 

Are there pros and cons to the diet?
The blue zone diet can be nutrient-rich from the consumption of fruits, vegetables legumes etc., which can develop and support good health. This in turn, alongside other benefits of the diet can lower chronic disease risk such as heart disease.

The recommendations for regular activity relate closely to scientific recommendations and are associated with improvements and maintenance of bone mass. In addition, there is a requirement to address the decline in muscular mass as we get older (Sarcopenia) which regular exercise and tailored, healthy diet can help alleviate. Another benefit of a healthy diet and exercise regime is weight management. With an emphasis on plant-based foods, which are more fibre-based, can help with weight loss and maintenance.  

I must mention the potential for limited Protein sources. Those who are used to consuming regular animal proteins may find it challenging to get adequate protein from plant sources and so tailoring to meet requirements should be considered.  

In addition, nutrient deficiencies can be a common issue with this dietary approach if not carefully monitored, the diet could lead to deficiencies in vitamins B12 and D (which could be offset somewhat by the climate), iron, calcium, and omega-3 fatty acids, which are more readily available in animal products. It depends on the level of conformance with the diet and your approach i.e., vegan, vegetarian, pescatarian. There are numerous factors to consider. 

Organic plant-based foods can be challenging in some areas and may be more expensive than diets that rely on processed foods and cheaper meat cuts. 

In summary, while the Blue Zones diet can offer considerable health benefits it requires careful planning to ensure nutritional adequacy and may not suit everyone's lifestyle or dietary preferences. Lastly, planning for adoption of the approach should consider implanting sustainability of the approach. As so often, with most diets, people will tend to stop at some point. It’s a lot of effort to employee unless it is considered for the long-term. 

Do you think it is just a diet or are there other factors at play? 
Yes, indeed there are multiple other factors at play here. We know that one aspect of longevity is the interplay between genetics, lifestyle/environment, behaviour, metabolism and degeneration. For this last aspect, how our cells function is important as our diet/genetics/lifestyle could all impact a process called ‘autophagy’ which means how the cells deal with damaged proteins.

The concept of the blue zones diet combined with an active lifestyle, lower stress (or better stress resilience) could be important in relation to how long our cells functional optimally. Interestingly there is some evidence that in certain locations like Costa Rica, the diet (mostly plant-based and some fruits) has been associated with telomere length which could also mean more ‘resilience’ over time. I do think the diet is big component of this, or rather that a poor diet likely accelerates aging and degenerative disease.

However, diet is only one part, and recent evidence points to the idea that more healthy dietary choices when stacked up and started earlier in life could be the difference between a life expectancy of say 73 years to over 85 years. That said, what is more important is the relative health of the individual, in other words can we maximise healthy lifespan not just extend our lives. 

What do you think is the take home message?
The word ‘diet’ is a not an accurate designation. The Blue Zone diet, as with other approaches can be a simple response to a complex issue. As such, effectiveness of the approach is determined by additional factors.

As touched on earlier, health care system effectiveness, finances, climate all have an influence on longevity. For instance, obesity has over 100 associated influences or variables so how many can associations with longevity can we envisage? For a sustained, effective approach to lifestyle change we need to take these additional influences into account and plan accordingly.  

Any change, such as dietary, activity requires a consideration as to whether they are compatible with lifestyle. However, the Blue Zone, in general is a good pointer towards a healthy lifestyle and similar approaches are recommended by health professionals and organisations. 

Lastly, any change in diet should be considered against the backdrop of risk. You should speak to a health professional prior entering any significant dietary approach. Do not be swayed by the claims, rather explore and gather the facts beforehand and make informed choices.