In many cases, the benefits of sports outweigh the risks of overexposure to pollutants.

Cycling and walking are two active modes of transport beneficial to health as they increase the body’s physical activity. But active transport also increases the amount of inhaled polluted air, which could have a negative impact on health.

So can we pedal safely in the city?

In 99% of cities, the benefit of sports is higher than the risk associated with pollution

An international team of researchers assessed the benefit/risk ratio of active transport in a polluted environment (2). The researchers modeled the effects of cycling and walking in different polluted environments and measured a duration from which there were no more health benefits. The effects on all-cause mortality were tested.

The study found that only 1% of the world’s cities have a level of pollution such that outdoor physical activities are detrimental to health: the health benefits of walking or cycling exceeded the risks associated with inhaling polluted air.

For Audrey de Nazelle, of Imperial College London, “The good news is that all over the world, in 99% of cities, it is safe to bike up to two hours a day.” According to Marko Tainio, who conducted this research, “even in Delhi, one of the most polluted cities in the world with pollution levels ten times those in London” people should spend more than five hours a week cycling so the risks of pollution prevail over health benefits.”

It is still better to avoid the proximity of cars

A study of the Harvard School of Public Health (3) somewhat nuances this idea: by sharing the road with cars, a cyclist increases by more than 30% his exposure to air pollutants than if he pedals on a bicycle path separated from the road .

In the city, pollution emissions related to road traffic are responsible for a significant part of air pollution. Among the air pollutants are: fine particulate matter (PM 10 and PM 2.5, PM = particulate matter), nitrogen dioxide NO2, carbon monoxide (CO) and ozone (O3).

Researchers in Boston have measured the pollution along 5 of the city’s cycle routes, including bicycle lanes directly adjacent to the road, bicycle lanes separated from the road and roads shared by buses and bicycles. The researchers surveyed these routes by bicycle with a pollution measuring device. In particular, they have measured two known elements to increase cardiovascular risk and the risk of lung cancer: carbon black (black carbon) particles and nitrogen dioxide.

Carbon black particles are emitted by exhaust (including diesel engines) and represent a relevant tracer of road traffic pollution. Nitrogen dioxide is a toxic gas produced by combustion. It causes inflammation of the airways.

The results show pollutant concentrations are one-third higher on bicycle lanes adjacent to roads than on more distant cycle lanes. The air quality is particularly bad at the intersection where the cars stop and restart. Conclusion: if you have a choice, opt for the green routes.

And in the gym the air is also polluted

You want to get into the gym to avoid pollution? This may not be the best idea … The quality of the air in the gyms is influenced by the maintenance of the buildings, the building materials, the type of ventilation but also by the occupancy rate and the type of activities carried out.

In a recent study (4), researchers placed equipment to analyze air quality in gyms in Lisbon. Carla Ramos, author of the study, obtained permission from 11 gyms to dispose of the equipment to analyze the air quality in both the weight rooms and the small ancillary rooms. The devices have been programmed to analyze pollutants in the air in late afternoon and evening when attendance levels are higher. The researchers assessed the pollutants generally found in indoor air: carbon monoxide, carbon dioxide, ozone as well as airborne particulate matter (dust) and chemical products (including formaldehyde) released by carpets, cleaning products, furniture, paint.

Researchers found high levels of airborne particulate matter, formaldehyde, and carbon dioxide (CO2) in gyms. The concentrations of these pollutants exceeded the European standards generally accepted for indoor air quality. The levels of these pollutants were particularly high during aerobics classes, during the time when people are confined in small rooms, move a lot and breathe heavily.

High concentrations of particulate matter and chemicals, such as formaldehyde,  in the air are the most worrying problem. “They can cause asthma and respiratory problems,” says Carla Ramos. “Carbon dioxide, even if it is not toxic, could also be a source of concern.” At high concentration, it can train physical fatigue and cognitive confusion, which is not desirable during an aerobics course, adds Carla Ramos.

References

(1) Chen H1, Goldberg MS, Villeneuve PJ. A systematic review of the relation between long-term exposure to ambient air pollution and chronic diseases. Rev Environ Health. 2008 Oct-Dec;23(4):243-97.

(2) Tainio M, de Nazelle AJ, Götschi T, Kahlmeier S, Rojas-Rueda D, Nieuwenhuijsen MJ, de Sá TH, Kelly P, Woodcock J. Can air pollution negate the health benefits of cycling and walking? Prev Med. 2016 May 3. pii: S0091-7435(16)00040-2. doi: 10.1016/j.ypmed.2016.02.002.

(3) The Boston Globe. Cyclists, don your gas masks. By Kevin Hartnett.

(4) C.A. Ramos, H.T. Wolterbeek, S.M. Almeida. Exposure to indoor air pollutants during physical activity in fitness centers. Building and Environment 82 ( décembre 2014) 349-360

Can we do sports when we live in a polluted city?
Nutrition and Innovation

Athletes who receive omega-3 fatty acid supplements have improved muscular function and less muscular fatigue

A new study by researchers at the University of Toronto and published in the Journal of the International Society of Sports Nutrition reports omega-3 fatty acid supplements can improve neuromuscular function and reduce muscular fatigue among athletes. Those who received omega-3 for 3 weeks had a 20% increase in their muscular function in the thigh.

Omega-3 fatty acids are polyunsaturated fatty acids in the form of long chains in fatty fish, shells, crustaceans, and chicken eggs fed with flax seeds. They can also be synthesized from the alpha-linolenic acid of rapeseed, flax seeds, walnuts…

“The ability of skeletal muscles to generate strength and withstand fatigue is essential in sports performance,” explain the authors in their article. “Training adaptations of skeletal and neuromuscular muscular systems modulate the ability to generate muscular strength and fatigue resistance.”

“Many studies have evaluated the effect of nutritional supplements on bodybuilding (protein supplementation) and methods for enhancing endurance performance (carbohydrate load).” But to date, few studies have focused on the effect of nutritional supplements on the neuromuscular system.

The central and peripheral nerves are composed of fatty acids, essentially polyunsaturated. “Omega-3 is an integral part of neurons, nerve endings, myelin and muscle membranes.” And more and more evidence suggests that omega-3 improves neuronal function and adaptations to exercise. “Omega-3 supplementation would be able to improve the velocity of nerve conduction, membrane fluidity, sensitivity to acetylcholine and also reduce inflammation after exercise.”

The researchers conducted their study on 30 male athletes on average 25 years old and trained about 17 hours per week. Participants received either the seal oil supplement containing long chain omega-3 (375 mg eicosapentaenoic acid EPA, 230 mg docosapentaenoic acid DPA, 510 mg docosahexaenoic DHA acid per day) or placebo for 3 weeks. The athletes passed tests at the beginning and end of the study.

The results show omega-3 supplements are associated with a significant increase in the level of EPA in the blood compared to placebo-receiving participants. But the researchers did not find any difference between the two groups for the levels of DPA and DHA.

Omega-3 supplements allowed a 20% increase in muscle function of the thigh, evaluated by electromyography of the extensive external muscle, compared to placebo. Omega-3 supplements were also associated with a reduction in muscle fatigue.

“To our knowledge, this study is the first to evaluate the effects of omega-3 fatty acid supplementation on athletes by measuring both the changes in neuromuscular function and performance,” the authors say. “This study shows omega-3 supplements increase muscle activation and reduce fatigue.” According to the authors, there is sufficient evidence to conclude omega-3 has a beneficial effect among athletes.

The authors explain that omega-3 modifies the composition of the cell membrane and its fluidity, which could stimulate the nerve function. “Omega-3 supplementation may have altered the membrane dynamics of the muscle and improved the conduction of muscle action potential through the working muscle.” “Altering the membrane dynamics may have attenuated muscle damage.”

Similarly, in the group having received omega-3, the attenuation of muscle damage could maintain the conduction of the action potential in the muscle, now thus the excitation-contraction coupling and finally the generation capacity of muscular strength.

This study is in addition to the already existing evidence of omega-3 benefits in the nutrition of the athlete.

Reference

Lewis EJ, Radonic PW, Wolever TM, Wells GD. 21 days of mammalian omega-3 fatty acid supplementation improves aspects of neuromuscular function and performance in male athletes compared to olive oil placebo. J Int Soc Sports Nutr. 2015 Jun 18;12:28. doi: 10.1186/s12970-015-0089-4. eCollection 2015.

Omega-3 improves sports performance
Nutrition and Innovation

Physical activity fights against inflammation, and the more you do it, the more it decreases.

Running, swimming, biking, tennis … Physical activity has many benefits, especially because it helps reduce inflammation. An article in the European Journal of investigation explains how physical exercise works.

The longer it is, the better

Chronic inflammation is linked to all kinds of diseases including type 2 diabetes and heart disease. But when muscles work, muscle cells release interleukin-6 (IL-6) and interleukin-10 (IL-10), two mediators playing an important role in the fight against inflammation.
Il-6 and IL-10 act both by decreasing the levels of TNF-alpha protein, itself causing inflammation in the body but also by inhibiting the signaling effects of the interleukin-1-beta protein which causes inflammation and damages the pancreas cells.

According to the authors of the article, longer the duration of physical activity, the greater the amount of IL-6 released-the first cytokine detectable during physical activity is important. For example, after a 30 minute workout, IL-6 level can be multiplied by 5 while after a marathon it can increase by a factor of 100. The level of IL-6 increases until the end of the physical activity session and then decreases rapidly to return to the level of prior physical exercise.

Interleukins 6 and 10 are not the only molecules involved in the anti-inflammatory effect of physical activity. For example, studies have shown regular exercise increases the level of interleukin-15 in muscle cells. However, IL-15 reduces the accumulation of abdominal fat, which itself promotes inflammation. By reducing abdominal fat, physical exercise therefore fights against inflammation.

In practice

“Physical activity represents a natural method for combating inflammation and improving metabolism should be part of the treatment of people with chronic diseases such as diabetes or heart disease,” concludes the article. In practice, chronic inflammation can be reduced from 20 minutes of walking. If you’re not athletic but you want to get on with it, we can progressively intensify the rhythm of the outings, of sports sessions from 15 to 40 minutes of running at slow pace (30 minutes to 2 hours biking (or 10 to 20 minutes of running time (20 minutes to 1 hour) with a steady pace.

A natural anti-inflammatory: running (pedaling, swimming…)
Nutrition and Innovation

Among professional athletes, training associated with dietary proteins would stimulate the diversity of the intestinal flora.

For a healthy and diversified intestinal flora, it would be better exercising than eating yoghurts with active bifidus. According to an Irish study, sports associated with a large consumption of proteins would promote the bacterial diversity of the intestinal flora.

Intestinal flora plays an important role in digestion, but also immunity. An intestinal flora whose diversity is reduced is associated with obesity and health problems. On the other hand, a diversity of the bacterial species present in the intestinal flora is linked to favorable metabolic profiles and a better immune response.

To learn about the impact of physical exercise on the intestinal flora, researchers have been interested in professional rugby players. Indeed, the lifestyle could influence the composition of the intestinal flora. The fecal and blood samples of 40 professional players who participated in an intense training program were compared with those of 46 healthy men. The witnesses were not professional athletes but their ages and sizes matched those of the players. All participants filled out food questionnaires and answered questions about their physical activity.

The researchers have dosed the level of creatine kinase in the blood, an enzyme marker of muscle damage and therefore is proof of an extreme exercise. Athletes had high amounts of creatine kinase but levels of markers of low inflammation. The diversity of their intestinal flora was greater, with a number of different bacterial types more important. For example, athletes had more akkermansiaceae, bacteria associated with low rates of obesity and metabolic disorders.

Overall, rugby players ate larger amounts of all types of food. But proteins accounted for 22% of their energy intake compared to 15-16% for the control group. This was explained by the consumption of meat and meat products but also of protein dietary supplements. The athletes also ate more fruits and vegetables.

For the authors, these results show that exercise, in addition to diet, is an important factor in the microbial diversity of the intestinal flora.

Reference

F. Clarke, E. F. Murphy, O. O’Sullivan, A. J. Lucey, M. Humphreys, A. Hogan, P. Hayes, M. O’Reilly, I. B. Jeffery, R. Wood-Martin, D. M. Kerins, E. Quigley, R. P. Ross, P. W. O’Toole, M. G. Molloy, E. Falvey, F. Shanahan, P. D. Cotter. Exercise and associated dietary extremes impact on gut microbial diversity. Gut, 2014; DOI: 10.1136/gutjnl-2013-306541

Exercise promotes the diversity of the intestinal flora
Nutrition and Innovation

Plunging into cold water after exertion decreases aches.

The body aches are caused by micro-traumas to the muscular fibers after a sports training. A normal phenomenon but can be problematic by preventing the athlete from quickly resuming his training at full capacity.

Many people are struggling to endure these pains sometimes even to the point of not doing sports anymore. This is not advisable because with the workout your muscle fibers strengthen and the aches decrease over time, sometimes going as far as disappearing. Meanwhile, researchers have validated a method which has been used for a few years by high-level athletes to reduce body aches: cold baths.

Researchers from the Cochrane group reviewed all studies on the use of cold baths to prevent aches, compared to rest. After analyzing 19 studies they conclude that cold baths are effective in solving this problem. But be careful, cold baths must be at a temperature of 15 degrees maximum and last at least 15 minutes. On the other hand, researchers indicate that the efficiency of cold baths is not demonstrated in comparison with active recovery methods (return to sports quickly with light training to accelerate the disappearing of the pain) for which new studies are needed but the cold baths have the advantage of saving time and being simple to set up.

How do cold baths reduce body aches? The micro-traumas to the muscular fibers that are causing the body aches are responsible for calcium leakage within the fibers. This phenomenon is toxic and triggers a delayed inflammatory reaction, hence the onset of aches 24 to 48 hours later. The sensitivity of muscle fibers to calcium depends on the temperature: it increases when it’s hot and decreases when it’s cold. By dipping into an icy bath after effort, the toxicity of calcium is reduced and thus the release of the inflammatory substances causing the pain. But the anti-inflammatory effect of the cold is in fact known for a long time: this is why ice pockets are applied to certain wounds.

Reference

Bleakley C., McDonough S., Gardner E., Baxter G. David, J. Ty Hopkins, and Gareth W Davison. Cold-water immersion (cryotherapy) for preventing and treating muscle soreness after exercise. The Cochrane Library, Feb 2012.

A cold bath against muscle soreness
Nutrition and Innovation

Today, each of us produces an average 590 kg of waste per year! Sorting is clearly not enough. The only viable solution is to generate less. Let’s see how to reduce the volume of our bins easily.

To avoid producing waste, you have to know how to buy the right products and then use them. Here are 10 gestures allowing you to consume more responsibly:- by preserving the resources used for making objects, some of which are not renewable;- by limiting the pollution of water and soil, greenhouse gas emissions and reducing the costs of collection, processing and storage.

1. Use reusable bags or baskets

The lifespan of disposable bags is very short: they are usually thrown after only 20 minutes. When they are abandoned in nature, it’s worse since they are ultra polluting and put 200 years to degrade when they are plastic. 17 billion of single-use plastic bags are consumed every year in Europe, of which 8 billion are abandoned in nature.

In several European countries, stores will no longer be able to offer disposable plastic bags from January 2016. But note that paper alternatives are hardly practical (more fragile and less comfortable).

By using a shopping bag or reusable bag, you can reduce your packaging waste. There are sturdy, pretty, pocket-sided shopping bags to have them ready to use, for shopping’s of the week.

2. Choosing the right packaging

Focus on recyclable and ecological packaging, such as glass (jars) and aluminum cans (canned, coffee cans, etc.) which are recyclable for life. Prefer cardboard (recyclable) to plastic that is not recyclable.

Avoid overpacks (cardboard + plastic inside). For dairy, compotes, etc., prefer large containers to individual. If the composition of your home makes you use individual pots instead, choose the ones not surrounded by cardboard.

For low-perishable foodstuffs (tea, coffee, rice, pasta, flour, sugar, etc.), you should also prefer large packagings.

To keep and transport the children’s snacks, prefer a reusable snack box to individual sachets and other canteens.

3. Buy in bulk and cut

Meat, cooked meat, fish, seafood, cereals, vegetables, fruits, legumes but also screws and bolts or some detergents are available in bulk, retail or cutting. This makes it possible to take just the amount you need, to make a few savings while reducing your waste.

For this, you can use your own containers (plastic boxes, reusable paper bags, etc.) to do your shopping. You will quickly take on new habits.

4. Avoid food waste

By buying on a smart way, keeping your food well, by cleverly cooking you can avoid throwing food to save money.

Make a shopping list before you go to the store (by checking your stock), pay attention to the expiration dates at the store as at home, respect the types of storage indicated on the products, cook quantities adapted to the number of Eat at the table, accommodate the leftovers.

By limiting food wastage you are saving on food that has been discarded without being consumed and you are reducing your waste by 20 kg per year. In fact, each Europeans throws on average 7 kg of still packaged food to which we must add another 13 kg of leftover meals, damaged fruits and vegetables, unused bread…

5. Use your own cup in the office instead of disposable cups

Drinking your tea or coffee in a nice cup will increase the enjoyment of your break while reducing your waste. If the machines in your workplace doesn’t have a cup detector, check to see if it can be easily remedied.

6. Make better selections of equipment and gifts

Choosing a durable and repairable furniture or household equipment is an important environmental gesture.

Buying second-hand, renting or borrowing products which serve little is also a good reflex. Many websites now offer the opportunity to find second-hand objects or rent objects for short periods of time.

Also think of dematerialized gifts such as cinema or theatre subscriptions, a stay in lodge… such as things which will not be able to finish in the trash.

7. Making compost

Peelings vegetables, leftover meals, lawn mowing, dead leaves, hedge sizes, etc. can be composted on the ground in the garden or in a special tray. In an apartment, you can use a small indoor compost machine. Some cities even offer special bins that are exchangeable in waste against the result of composting, a quality natural fertilizer. A qualitative compost should be stirred once a month.

By making compost, you can reduce your waste by at least 60 kg per year.

8. Giving, selling instead of throwing

I have at home objects which I no longer have the utility but which are still in good condition so why throw them away? By giving the objects you no longer need but is still in a good condition, you can help your relatives or associations that might need them. By selling them second-hand, I can make a little extra money. By swapping them, I can acquire in exchange other items that I need and that will not cost me anything.

And in addition, by selling or giving the items in good condition that I no longer use, I can reduce my waste by 13 kg a year.

9. Limit paper print-outs

Printed documents get lost easily, must be stored so take up space, and end up costing a lot of paper, ink … In addition they diffuse less well than their electronic counterparts. Print if it’s really indispensable, you will reduce up to 6 kg of your waste per year.

10. Prefer rechargeable batteries

More expensive to buy, rechargeable batteries have a much longer lifespan than their disposable cousins. Rechargeable batteries are beneficial: long term money savings but also time since you no longer need to go to the store to look for new ones when they are discharged. Not to mention they avoid you from rejecting polluting waste.

The best waste is the one that is not produced.

10 simple steps to reduce our waste
Nutrition and Innovation

The increase in the amount of atmospheric CO2 could lead to protein deficiency among millions of people around the world.

Climate change increases the risk of heat waves, floods, some diseases, extinction of species… and, according to a Harvard university study which has just appeared in Environmental Health Perspectives, it could also make our diet less nutritious.

Today about 76% of the world’s population pulls most of its protein from plant sources, such as cereals. These agricultural productions are dependent on the climate and the atmospheric CO2 rate.

For this study, the researchers combined the results of experiments on cultures exposed to high concentrations of CO2 with food, economic and demographic information. According to their results, if CO2 levels continue to rise, rice, wheat, barley and potato protein will decrease by 7.6%, 7.8%, 14.1% and 6.4%, respectively. Thus, the standard diet of an Indian would lose 5.3% of protein. These results suggest that 150 million more people may be in protein deficiency due to elevated CO2 levels.

If CO2 levels continue to rise as planned, 18 countries may lose 5% of the food protein from crops such as rice or wheat in 2050. At the same time, livestock could be less productive because of high temperatures. In addition, global warming could also cause exceptional climatic events such as hurricanes complicating agricultural yields.

For Samuel Myers, one of Harvard’s researchers, “this study stresses the need for countries most at risk to actively monitor the nutritional sufficiency of their populations and, more fundamentally, the need for countries to curb Man-made CO2 emissions.”

Another article published in August 2017 suggests that iron content will decrease in crops, also because of high levels of CO2, which would lead to deficiencies and therefore anemias, especially among children under five years old and women who lives in the countries of Southeast Asia and North Africa.

Less protein in cereals because of global warming?
Nutrition and Innovation

Vitamin and fatty acid supplements have shown their interest in preventing damages induced from pollution.

According to World Health Organization (WHO), 92% of the world’s population will live in areas without meeting the air pollution limits set by the WHO. Fine particulate matter pollution PM2.5 (diameter less than 2.5 µm) raises health problems as these pollutants drop into the airways, where they can cause inflammation. Exposure to pollutants is associated with higher rates of cardiovascular and respiratory diseases and mortality, especially in the city. Despite the policies aimed at reducing air pollution, pollution peaks are frequently recorded.

But it may be interesting to consider taking some nutritional supplements to protect ourselves.

Group B vitamins

Air pollution acts on our genes. Specifically, it can alter DNA by an epigenetic mechanism, such as DNA methylation. These epigenetic modifications do not change the DNA sequence itself but are involved in important health phenomena, such as oxidative stress and inflammation.

In an article published in PNAS (Proceedings of the National Academy of Sciences of the United States), international researchers wanted to know whether vitamin B supplements could prevent the harmful effects of PM2.5 particles. B vitamins (including B6, B12 and folate) are cofactors in methylation reactions.

For this, the researchers gave either a placebo or a supplement of vitamin B (2.5 mg folic acid, 50 mg of vitamin B6 and 1 mg of vitamin B12) each day to the volunteers of the clinical trial. 10 of the volunteers were healthy people who did not smoke and were aged 18-60. PM2.5 particles were issued to the participants at a concentration of 250 µg/m3, using a mask. The study showed the epigenetic effect of air pollution: the fine particles induced changes (methylations) in genes implicated in the energetic metabolism of mitochondria (the energy plants of the cells).

The results also suggest that B vitamins could be used to prevent and mitigate the effects of air pollution on the epigenome because complementation prevented epigenetic changes.

Vitamins C and E

These two vitamins are antioxidants. In one study, the effects of vitamin C (500 mg/d) and vitamin E (800 mg/d) supplements were studied for 6 months among individuals exposed directly or indirectly to particulate emissions from a coal-fired power plant. Compared to the control group, those who received the vitamins saw the markers of oxidative damage drop and the levels of the antioxidant and nonenzymatic enzymes increase (glutathione, sulphur proteins, catalase, enzymes to glutathione).

Omega-3

In a controlled randomized trial, the effect of omega-3 (2 g fish oil/day) or placebo on the cardiovascular response to fine particulate matter was evaluated among institutionalized elderly people. Results: omega-3 fish oil warned of the negative impact of PM2.5 on cardiac variability, a marker of cardiovascular risk.

In another study, omega-3 (2 grams per day) increased the activity of an antioxidant enzyme, SOD (superoxide dismutase), 49% and the level of glutathione (main cell detoxifying) by 62%. Fat oxidation decreased by 72%. Thus, omega-3 appears to modulate the oxidative stress induced by PM2.5 particles by increasing the activity of the body’s antioxidants.

Reference

Péter S, Holguin F, Wood LG, Clougherty JE, Raederstorff D, Antal M, Weber P, Eggersdorfer M. Nutritional Solutions to Reduce Risks of Negative Health Impacts of Air Pollution. Nutrients. 2015 Dec 10;7(12):10398-416. doi: 10.3390/nu7125539.

Air pollution: food supplements protecting the body
Nutrition and Innovation

More and more studies show a natural environment is good for your health.

Less pollution, less stress, facilities to do sports, sunny, positive effects on mental or immune health… The benefits of living away from city centers are increasingly proven. Here are some arguments before you prepare your suitcases.

Lower mortality when living near nature

Researchers at the Harvard University Public Graduate School and the Brigham and Women’s Hospital wanted to examine the association between vegetation presence and mortality. For this, they used medical information on 108 630 women from the Nurses’ Health Study (USA) between 2000 and 2008. The mortality risk was compared with the level of vegetation present around the dwellings, measured by satellite imagery. There were 8 604 deaths over the period studied.

The 20% of women with the most vegetation in their environment (for 250 m around) had 12% less mortality than those with the least vegetation. This association was particularly strong for respiratory and cancer mortality: women living in areas with the most vegetation had 34% risk in fewer deaths from respiratory diseases compared to those with the least vegetation. These associations are explained by factors such as: physical activity, the presence of particles less than 2.5 µm, social life, mental health, exposure to air pollution, noise, or stress.

These results should encourage urban planners to incorporate more vegetation into urban areas.

Living in the mountains to keep your figure

According to a study of American soldiers, overweight people living at high altitudes would have less risk of tipping into obesity than those living at low altitudes. When the altitude rises, the air pressure decreases and the body has more difficulty in supplying oxygen: it’s in a situation of hypoxia. Studies have shown a reduction in appetite and body fat in conditions of hypoxia.

The researchers questioned whether hypoxia could limit the risk of obesity. They studied nearly 100 000 overweight soldiers stationed at different elevations in the United States, between 2006 and 2012. Some were assigned at high altitudes, more than 1 960 m, and others at low altitudes, i.e. less than 980 m.

Results: Soldiers assigned at high-altitude had a reduced obesity rate of 41% compared with those at low altitudes. These results appear to be confirmed by observations made on the civilian population: in fact, the American city where one is the thinnest is Boulder, Colorado, at 1 650 m altitude; the American city where one is the largest would be Huntington, West Virginia, located at 171 m altitude only.

This beneficial effect of altitude on weight could be explained for hormonal reasons because hypoxia is associated with an increase in leptin, a hormone suppressing appetite. Cholecystokinin, which stimulates the digestion of fats and proteins, and noradrenaline, which influences appetite by reducing blood flow to the intestine, both increase at high altitude.

In the countryside for good immunity

The idea that an increase in immune disorders (asthma, allergies…) in Western countries is linked to an excess of hygiene is not new: according to the hygienist hypothesis, our immune system would be less in contact with environmental micro-organisms, which would cause chronic inflammation problems.

Some important infections for immune development have been eliminated from developed countries. With urbanization, contacts with animals, green spaces, and therefore micro-organisms of the environment have diminished. The microbial diversity presents on the skin, in the intestine, the lungs has decreased; at the same time, micro-organisms in the environment have become less numerous due to better hygiene.

Because of the loss of old infections, the immune system would have become more dependent on microbiota, such as intestinal flora, and the environment. This is why exposure to environmental micro-organisms such as those which can be found in the countryside would play an important role. This would explain why people living in urban centers with little access to green spaces would suffer more chronic inflammation, as Christopher Lowry explains: chronic inflammation can lead to all kinds of problems, From irritable bowel syndrome to asthma, allergies and even depression.

At sea, health is also better

Spending the time near the sea has a beneficial effect on health. This is what researchers at the University of Exeter (England) say at a conference of the American Geophysical Union. A stay at the beach allows you to expose yourself to the sun and therefore to make the full of vitamin D. But that is not the only health benefit.

Researchers have studied the health of English populations at different points in the territory. They showed those who lived near the coasts had a better state of health. The reasons for this are different: living near the coast reduces stress but also encourages physical activity. Two positive health effects.

Another indication of the beneficial effect of the sea on well-being: an experiment carried out by the researchers. They proposed to different people pictures corresponding to views of hotel rooms; they asked them how much they were willing to pay for the room. Between a view of the sea, the green countryside or the city, most would have paid the most expensive to have a sea view.

References

James P, Hart JE, Banay RF, Laden F. Exposure to Greenness and Mortality in a Nationwide Prospective Cohort Study of Women. Environ Health Perspect. 2016 Apr 14.

Voss JD, Allison DB, Webber BJ, Otto JL, Clark LL.. Lower Obesity Rate during Residence at High Altitude among a Military Population with Frequent Migration: A Quasi Experimental

Model for Investigating Spatial Causation. PLoS One. 2014 Apr 16;9(4):e93493. doi: 10.1371/journal.pone.0093493. eCollection 2014.

Rook Graham A.W., Raison Charles L, Lowry Christopher. Microbial “Old Friends”, immunoregulation and socio-economic status. Clin Exp Immunol. 2014 Jan 9. doi: 10.1111/cei.12269.

Jeff Watters, Fred Tyson, Paul Sandifer, Margaret Leinen (modératrice) et Lora Fleming.The Changing Ocean and Impacts on Human Health. AGU science policy conference. 26 juin 2013.

Sea, mountain, countryside: where to live to be healthy
Nutrition and Innovation

Agricultural yields are higher with polyculture than with monoculture.

While modern agriculture promotes monoculture on the same plot, French researchers from the Centre for functional and evolutionary ecology (CEFE-CNRS/Université de Montpellier) and Inra from Lusignan have just shown that the polycultures have a better yield than monoculture, especially in drought conditions. The results are published in the journal Nature Plants.

The study, which lasted a year and a half, focused on 5 forage plants, with monoculture plots and others associating the 5 plants. The genetic diversity was also varied by the researchers. Some plots have been irrigated and others weren’t irrigated, to check the behavior of plants in a drought situation.

In irrigation, the yield of mixed-plant plots was greater than the monoculture plants of 200 grams per m2, or 2 tons per hectare. In a drought situation, the difference has been increased to 8 tons per hectare. The yield of plots containing ten different genotypes of the same species was more stable than those with a single genotype.

This study suggests that biodiversity, such as permaculture practice, is more interesting to improve yields than the current model.

The principles of permaculture validated by a scientific study
Nutrition and Innovation