Nutrition is something that is talked about every day. Books and articles have been written about it, and today there is no simple recipe. Each of us ingests large amounts of food over the years. It can help us but also undo it, it depends on what attitude we have towards the diet. There are a lot of types of diets and diets, but it is best to find some balance in everything. We can find balance in our diet by examining ourselves and our limits. In addition to examining boundaries, we can find ideas on the internet or get advice from nutritionists.
To learn much more about this, check out the article by Prof. Jacques Proust.
What role does our diet play in ageing?
We age because the macromolecules that make up our bodies (proteins, lipids and nucleic acids) are progressively damaged. Due to this molecular alteration, certain essential biochemical reactions change, affecting the proper functioning of cells. This alteration in cellular metabolism in turn leads to disruptions in the functioning of organs and systems, and ultimately to a general physiological decline and the onset of disease. It is generally believed that our resistance to ageing is determined 30% by our genes and 70% by the environmental and behavioural influences to which we expose our organism, and in which diet also plays an essential role. These interactions between genetic and environmental/behavioural factors take place throughout life. Some epigenetic mechanisms of ageing can be counteracted by preventive intervention through nutrition – for example, through calorie intake and the composition of our daily diet – as long as this is done early on.
What influence does nutrition have on health in the course of ageing and on lifespan?
Depending on our genetic make-up and life history, some organs and systems age faster and show physiological damage earlier (cardiovascular diseases, neuro-degenerative diseases, chronic inflammation, demineralisation of bones, loss of muscle mass, skin changes, etc.). In addition to specific treatments for these diseases, appropriate dietary changes can slow down the development of these physiopathological changes and most likely increase life expectancy. Advanced age in itself is a risk factor for an unbalanced diet and various nutrient deficiencies. It is well established that ageing affects both the absorption of certain nutrients and their intake in general, due to physiological, psychological and social changes. However, a clear distinction must be made between the nutritional status, satisfactory at first sight, of older people who are in good health and living at home, and the significantly worsened nutritional status of less mobile people suffering from multiple diseases and housed in medical institutions. However, the results of European nutritional studies show that the vitamin intake of older people is often well below the recommended guideline values. The same applies to protein intake. For this sensitive population group, one should not hesitate to establish nutrient balances in order to identify and correct any deficiencies.
What is it about the Mediterranean diet and the Okinawa diet?
A traditional Mediterranean diet over a long period of time is associated with an increase in longevity and a decrease in the risk of chronic diseases such as cancer, metabolic syndrome, depression, and cardiovascular and neuro-degenerative diseases. Studies show that some dietary components such as olive oil, antioxidants, omega-3 and omega-6 polyunsaturated fatty acids, polyphenols and flavonoids are directly linked to the anti-ageing effects of this diet.
The inhabitants of the Japanese archipelago of Okinawa are known for their long life, the large number of centenarians and their low risk of developing age-related chronic diseases. This result is partly due to a traditional low-calorie diet. However, most of the characteristics of the Okinawa diet are also found in the Mediterranean diet: low consumption of meat, saturated fats, sugar, salt and large intake of phytonutrients in the form of antioxidants and flavonoids. In addition, the traditional herbs and spices of this diet may play a role in maintaining health in old age.
Which foods to prefer, which to avoid?
Of course, a balanced diet with the health-promoting nutrients of the above-mentioned Mediterranean diet is recommended and the basic advice for good nutrition remains valid, regardless of age:
– Shop at the market to get fresh foods that still contain the nutrients needed for our cells to function properly. Avoid industrially prepared convenience foods.
– Cook dishes at a temperature below 90°C (steaming, braising) to preserve all the proteins, vitamins and minerals contained in the food.
– Give preference to slow carbohydrates at every meal (wholemeal cereals, wholemeal sourdough bread, brown rice…) and avoid refined sugars as they upset blood sugar levels and insulin production.
– Avoid saturated fats and preferably use oils from the first cold pressing (olive oil, rapeseed oil, nut oils) to refine salads.
– Eat fruit and vegetables at every meal (4 to 6 portions daily), preferably cruciferous vegetables (all types of cabbage).
– Eat more dried fruits and pulses, especially oily fruits such as almonds, nuts and hazelnuts (12 nuts or hazelnuts per day).
– Eat fatty fish twice a week (salmon/herring/mackerel) and pay attention to the method of preparation.
– Eat enough protein (0.6 g of high-quality protein per kilogram of body weight daily), preferably in the morning and at noon instead of in the evening.
– Limit or stop salt consumption and replace salt with potassium salt (K-salt).
– Adjust calorie intake to energy expenditure (physical activity).
Do vitamin supplements, antioxidants and other food supplements bring benefits?
An unbalanced diet and/or nutrient deficiencies must of course be corrected accordingly after diagnosis (dietary supplementation with proteins and energy, vitamins, minerals, etc.). However, it has also been shown in the course of numerous studies that the uncontrolled intake of several food supplements is unnecessary and sometimes even harmful. The unregulated and often unreasonable dietary supplementation with numerous multivitamin compounds used at the same time can even become dangerous, as these are also contained in various special products on the market, thus creating the risk of overdosing on certain elements (such as vitamin A or selenium). The medical prescription of nutritional products enriched with bioactive compounds with health-relevant effects (nutraceuticals), selected on the basis of convincing clinical studies (evidence-based medicine), can be helpful in the prevention or even correction of certain physio-pathological changes associated with ageing. In the field of nutritional genomics (nutrigenomics and nutrigenetics) with the aim of understanding the molecular interactions between bioactive compounds in foods and the genome are promising. Indeed, certain foods are thought to influence the expression of specific genes, for example by altering their level of methylation or acetylation. These epigenetic changes play an important role in both the occurrence of cancer and the ageing process. Optimising nutrient intake according to an individual’s genetic characteristics should enable personalised nutritional counselling with the aim of modifying any risk factors that may have been identified. In a related field of research, thanks to high-throughput collective genome sequencing, it is now possible to study the microbiome, that is, all the genomes of the microorganisms that live in symbiosis in our organism in a healthy state. In the near future, this analysis will make it possible to describe the interactions in this bacterial ecosystem more precisely, but also those between the different microbial communities and the organs or the organism as a whole. The aim is to repair certain dysfunctions and resulting (also age-related) diseases by prescribing selected living microorganisms added to certain (probiotic) foods in the form of supplements and/or administered in the form of selective substrates to stimulate the growth of favourable (prebiotic) bacterial strains.
How does calorie restriction affect ageing?
In the 1930s, it was found that a 70% reduction in calorie intake immediately after weaning increased the lifespan of laboratory rats by up to 30% compared to rats fed ad libitum. Since then, this experiment has been reproduced several times with other animal species and other feeding strategies. The results are identical: calorie restriction, regardless of its origin and regardless of when it occurs, slows the ageing process. Calorie restriction without malnutrition improves most of the biological and physiological parameters usually affected by advancing ageing, while also reducing the incidence of age-related diseases.
How does this system work?
It was recently discovered that a universal genetic mechanism involving energy reserves, maintenance and repair mechanisms, and growth and reproductive processes appears to control the speed of the ageing process in most species. When food is abundant in the environment, the responsible genes preferentially use the available energy for growth, sexual maturity and reproduction. This strategy is accompanied by a relative neglect of resistance to stress and maintenance and repair activities, leading to faster ageing and earlier death. In times of scarcity, when food is not available, the remaining energy resources are used for survival mechanisms (maintenance and repair), while growth and reproduction are neglected. Ageing is thus slowed down and survival is prolonged so that organisms can wait for more favourable reproductive conditions.
Is such a restriction of calorie intake also possible in humans?
While a simple, natural diet is recommended, such as the Mediterranean diet, calorie restriction as in the experiments conducted is strongly discouraged in humans and is not practical in the long term. Certain biochemical pathways have been identified that link available energy in cells and resistance to ageing. Pharmacological research is focused on the discovery or development of molecules that “make” the cells of the organism believe that there is a shortage of energy so that they activate their maintenance and repair system. Some of these molecules already exist in nature or in the pharmacopoeia. They are called “calorie restriction mimetics”. The challenge now is to increase their functional capacity. The ultimate goal of this treatment strategy is to improve our resistance to ageing and maintain our health in old age.
Is nutrition a “source of eternal youth”?
In recent years, great progress has been made in understanding the biological mechanisms of ageing. One of the most important findings of research in this field is that age-related physiological decline is far less immutable and inevitable than previously thought. Nowadays, there are means that, although not rejuvenating, can significantly influence the speed of the ageing process and prevent or delay the onset of classic age-related diseases. The influence of nutritional status on the morbidity and mortality of older people has long been proven, and numerous study results suggest that adequate nutrition can prevent, delay and even repair certain age-related changes. In the coming years, nutritional interventions will certainly play a primary role in geriatric medicine.