Brisk walking associated with a slowing down of the aging process

Brisk walking associated with a slowing down of the aging process

OVERVIEW

  • According to a study of more than 400,000 participants, walking pace is associated with telomere length, a genetic marker of biological age.
  • Among the participants, aged 56.5 years on average, those who walked the fastest had telomeres whose length was equivalent to a biological age 16 years younger.
  • This association depended on the intensity of walking (speed) and not on the total amount of physical activity.

Telomeres are repetitive DNA structures found at both ends of chromosomes that ensure the integrity of the genome during cell division (see also our article on the subject). Each time a cell divides, the telomeres shorten, until they become too short and the cell can no longer divide; it becomes senescent and eventually dies. The accumulation of senescent cells in the organs of the human body contributes to the development of diseases related to aging and frailty. Researchers consider telomere length to be a marker of “biological age”, independent of an individual’s date of birth.

The benefits of walking on physical and mental health are well documented, but researchers wanted to know if brisk walking could also be associated with slowing biological aging, as estimated by telomere length. In the UK study, 405,981 participants with an average age of 56.5 years reported information on walking speed, either by self-report or by wearing an accelerometer-type recording device. Telomere length was assessed in leukocytes (white blood cells) by PCR from a blood sample from each of the participants. The results show that faster walking speed was associated with longer telomeres (younger biological age) regardless of the total amount of physical activity. Complex statistical analyses (bidirectional Mendelian randomization) suggest a causal link between walking speed and telomere length, but not the reverse, i.e., that the lengthening of the telomeres is not responsible for a greater walking speed. A causal link can only be established with certainty by well-controlled and well-conducted intervention studies.

The results of this study reinforce the importance of brisk walking for the maintenance of good health. An earlier study by the same researchers at the University of Leicester in the UK indicated that as little as 10 minutes of brisk walking was associated with longer life expectancy, up to 20 years longer when comparing fast walkers to slow walkers. Brisk walking can be done at any age, indoors or outdoors, and requires no special athletic skills or expensive equipment.

The cardiovascular benefits of avocado

The cardiovascular benefits of avocado

OVERVIEW

  • Avocado is an exceptional source of monounsaturated fat, with content similar to that of olive oil.
  • These monounsaturated fats improve the lipid profile, in particular by raising HDL-cholesterol levels, a phenomenon associated with a reduced risk of cardiovascular disease.
  • A recent study confirms this cardioprotective potential of avocado, with a 20% reduction in the risk of coronary heart disease observed in regular consumers (2 or more servings per week).

There is currently a consensus in the scientific community on the importance of favouring dietary sources of unsaturated fats (especially monounsaturated and omega-3 polyunsaturated fats) to significantly reduce the risk of cardiovascular disease and premature mortality (see our article on this subject). With the exception of fatty fish rich in omega-3 (salmon, sardines, mackerel), plant-based foods are the main sources of these unsaturated fats, particularly oils (olive oil and those rich in omega-3 like canola oil), nuts, certain seeds (flax, chia, hemp) as well as fruits such as avocado. Regular consumption of these foods high in unsaturated fats has repeatedly been associated with a marked decrease in the risk of cardiovascular events, a cardioprotective effect that is particularly well documented for extra-virgin olive oil and nuts.

A unique nutritional profile
Although the impact of avocado consumption has been less studied than that of other plant sources of unsaturated fat, it has been suspected for several years that this fruit also exerts positive effects on cardiovascular health. On the one hand, avocado stands out from other fruits for its exceptionally high monounsaturated fat content, with a content (per serving) similar to that of olive oil (Table 1). On the other hand, a serving of avocado contains very high amounts of fibre (4 g), potassium (350 mg), folate (60 µg), and several other vitamins and minerals known to participate in the prevention of cardiovascular disease.

Table 1. Comparison of the lipid profile of avocado and olive oil. The data corresponds to the amount of fatty acids contained in half of a Haas avocado, the main variety consumed in the world, or olive oil (1 tablespoon or 15 mL). Taken from USDA. FoodData Central.

Fatty acidsAvocado (68 g)Olive oil (15 mL)
Total10 g12.7 g
Monounsaturated6.7 g9.4 g
Polyunsaturated1.2 g1.2 g
Saturated1.4 g2.1 g

This positive impact on the heart is also suggested by the results of intervention studies that examined the impact of avocado on certain markers of good cardiovascular health. For example, a meta-analysis of 7 studies (202 participants) indicates that the consumption of avocado is associated with an increase in HDL cholesterol and a decrease in the ratio of total cholesterol to HDL cholesterol, a parameter which is considered to be a good predictor of coronary heart disease mortality. A decrease in triglycerides, total cholesterol and LDL cholesterol levels associated with the consumption of avocado has also been reported, but is, however, not observed in all studies. Nevertheless, the increase in HDL cholesterol observed in all the studies is very encouraging and strongly suggests that avocado could contribute to the prevention of cardiovascular disease.

A cardioprotective fruit
This cardioprotective potential of avocado has just been confirmed by the results of a large-scale epidemiological studycarried out among people enrolled in two large cohorts headed by Harvard University, namely the Nurses’ Health Study (68,786 women) and the Health Professionals Follow-up Study (41,701 men). Over a period of 30 years, researchers periodically collected information on the dietary habits of participants in both studies and subsequently examined the association between avocado consumption and the risk of cardiovascular disease.

The results obtained are very interesting: compared to people who never or very rarely eat them, regular avocado consumers have a risk of coronary heart disease reduced by 16% (1 serving per week) and 21% (2 servings or more per week) (Figure 1).

Figure 1. Association between the frequency of avocado consumption and the risk of coronary heart disease. The quantities indicated refer to one serving of avocado, corresponding to approximately half of the fruit. Taken from Pacheco et al. (2022).

There are therefore only benefits to integrating avocado into our eating habits, especially if its monounsaturated fats replace other sources of fats that are less beneficial to health. According to the researchers’ calculations, replacing half a serving of foods rich in saturated fat (butter, cheese, deli meats) with an equivalent quantity of avocado would reduce the risk of cardiovascular disease by approximately 20%.

Avocados are increasingly popular, especially among young people, and are even predicted to become the 2nd most traded tropical fruit by 2030 globally, just behind bananas. In light of the positive effects of these fruits on cardiovascular health, we can only welcome this new trend.

Obviously, the high demand for avocado creates strong pressures on the fruit’s production systems, particularly in terms of deforestation for the establishment of new crops and increased demand for water. However, it is important to note that the water footprint (the amount of water required for production) of avocado is much lower than that of all animal products, especially beef (Table 2). In addition, as is the case for all plants, the carbon footprint of avocado is also much lower than that of animal products, the production of an avocado generating approximately 0.2 kg of CO2-eq compared to 4 kg for beef.

Table 2. Comparison of the water footprint of avocado and different foods of animal origin. Taken from UNESCO-IHE Institute for Water Education (2010) 

FoodWater footprint
(m3/ton)
Beef15,400
Lamb and sheep10,400
Porc6,000
Chicken4,300
Eggs3,300
Avocado1,981