Tag Archives: healthy-living

Do you need to exercise if you are healthy?

14022436150_97d48f6579Exercise improves your health, even if you are fit.

What is the importance of exercise if you are young, fit and healthy? Researchers in Finland have tried to answer this question by studying male identical twins. As these brothers are identical at the gene sequence level, any difference should be due to lifestyle factors.

They recruited 10 healthy male identical twins between 32 and 36 years old, of which only one brother had been exercising regularly for the last three years. They then measured their body weight and fat percentages, assessed their glucose levels and insulin sensitivity, and calculated the volume of their brains’ grey matter using magnetic resonance imaging.

The active twins had a higher VO2max and less visceral fat than their sedentary brothers, even though their body weight was not that different. Their glucose levels were lower and their insulin sensitivity* was higher. They also had a higher volume of grey matter in those areas associated with motor control.

The researchers concluded that even among healthy young adults exercise makes a difference. This is important, as lower fitness levels, more visceral fat and poor glucose metabolism are associated with chronic diseases later in life. Obviously, the negative effects of being sedentary begin early!

You might wonder if you have taken up exercise because you have a more favourable genetic profile than sedentary people. If so, you would be healthier whatever you do. This study suggests that this is not the case and that exercise makes a real difference, since identical twins should have the same genetic profile. This does not mean that genes do not matter. They are very important indeed, but you can influence them by your lifestyle.

This is only a small study. It would be great to confirm it with larger ones, but it must be very difficult to find a large group of identical twins of the same sex and age group with different exercise habits.

* Insulin sensitivity = how sensitive the body is to insulin stimulation. Low sensitivity is associated with higher risk of diabetes type 2.

References:

Rottensteiner M, Leskinen T, Niskanen E et al. Physical acivity, fitness, glucose homeostasis, and brain morphology in twins. Med Sci Sports Exerc. 2015; 47(3): 509-518.

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Could exercising make you eat more?

Many people exercise in order to lose weight or to keep it under control, but does this make sense? It is beyond doubt that regular exercise will improve your health and well-being, but could it make you hungrier, and therefore make you eat more? If so, it would not make any difference for your waistline…

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© Andre Maritz | Dreamstime Stock Photos

In the November 2014 issue of Nutrients, Stephanie Howe and her colleagues published a review article discussing what we know today about this subject. There are still plenty of questions left, especially concerning women, as most studies have been done on men. Studies on women are indeed much more difficult to conduct since oestrogen influences appetite, and researchers therefore have to control for the menstrual status.

Stephanie Howe and her colleagues explain how hormones influence our appetite, and how exercise influences these hormones. They then discuss several studies which have investigated this problem, and finally they look at the impact of diet.

They come to the conclusion that if you are sedentary, an acute bout of exercise is likely to make you overeat. However, as you become well-trained, your body becomes better and better at matching your energy intake with your expenditure.

They also note that as intense exercise suppresses your appetite more, you have to pay attention to what you are having after hard workouts: you could be tempted to eat too little or too late, which will delay your recovery.

Their article is free for all to read, and I will just try to make a summary in lay terms.

What determines your appetite?

Appetite is very complex and influenced by a long list of factors, such as gastric motility, the status of your energy reserves, temperature, dehydration… Your brain receives all this information via hormonal and neural signals, integrates them and then stimulates or suppresses your appetite.

The involved hormones can roughly be divided into two types: tonic circulating and episodic hormones.

The tonic circulating ones reflect your energy reserves and suppress your appetite when your energy stores are full, and are thus more involved with long term regulation. The best known ones are insulin and leptin.

The episodic hormones on the other hand are involved in short term appetite. Most of them are gut hormones and are released when you are eating or just before a meal. They suppress appetite, except for ghrelin, which makes you feel hungry. As their levels depend on what you are eating, it is easy to see why some diets make you feel fuller than others. Foods rich in fibres for example, will allow you to take in fewer calories without feeling hungry.

As mentioned earlier, oestrogen and progestogen also influence appetite, which explains why many women tend to gain weight during the menopause.

All these hormones act on the hypothalamus (an organ in your brain), which integrates the information and controls your appetite. Despite this sophisticated system, other factors, such as the sight and smell of food, cultural and social elements or the time of the day, also influence your desire to eat and can even override the hormonal influences.

Working Up Sweat (ID: 74747)
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Studying appetite

Researchers who want to study the influence of exercise on appetite therefore have to measure the amount of the appetite hormones in your blood as well as your desire to eat. The first can easily be done by a blood test, and the latter is often done using a visual analogue scale (VAS) or by measuring what the participants eat at a buffet in the research centre. A visual analogue scale typically consists of a series of numbered boxes (e.g. from 1 to 10), where the first and the last ones correspond to the extremes (e.g. “I’ve never been so hungry” and “I couldn’t eat anything at all”). You can then mark the box that corresponds best with how you are feeling.

Appetite hormones and exercise

A bout of aerobic exercise decreases your appetite by influencing your gut hormones. This effect is more pronounced in weight baring and more metabolic demanding exercise, such as running, than in non weight baring exercise.

Intense exercise influences the hormones more than moderate exercise. This suppression is only temporarily, but it can be enough to interfere with your next meal, and therefore with your recovery. This explains why it is so hard to eat anything solid after a race!

Resistance exercise on the other hand, does not seem to have an influence.

Are you really eating less?

It is not because your hormones are suppressing your appetite that you will eat less. As I am sure you know by experience, you can override your appetite if the food looks nice or if you believe you have good reasons to eat (e.g. I have spent a lot of calories, I need some comfort after all this hard work…).

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© Ragne Kabanova | Dreamstime Stock Photos

Most studies looking into energy intake after exercise do so by measuring what the participants eat at a buffet offered by the researchers. This does not necessarily simulate real life and might therefore lead to false conclusions. Even so, there is evidence that trained people are able to match their energy intake to what they have spent, and can therefore maintain a healthy weight. Sedentary people however, are more likely to overeat after an acute bout of exercise.

Diet

Most athletes are health conscious and will choose a diet rich in fruit, vegetables, whole grains etc…Such a diet will contain fewer calories per volume than an unhealthy one. It will also make you feel full much earlier. For the vast majority of us this is excellent news, but the combination of a low calorie diet, intense exercise and appetite suppression can become a trap for some athletes. It can lead to a chronic negative energy balance, and is more often seen in women engaged in sports for which being lean is an advantage, such as long distance running. It can lead to menstrual disorders with all their complications: poor bone health, injury, illness…

Recovery

If you want to recover quickly, you have to refuel as soon as you can. This can be difficult if your appetite is suppressed. Other factors such as fatigue, dehydration, an elevated core body temperature or gastrointestinal problems can make things even trickier. A good recovery drink can help you out though, as drinking is much easier than eating.

 

Exercise and a family history of type 2 diabetes

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© Kiankhoon | Dreamstime Stock Photos

Type 2 diabetes is more and more frequent in our Western world. It is probably the result of a complex and not- well-understood interaction of genes, lifestyle and obesity.

The disease starts with insulin resistance, which means that your tissues do not respond that well to stimulation by insulin. However, insulin is essential for the transfer of glucose from your blood into your tissues. As your tissues become resistant, you need more insulin to do the same job as before. If moreover the producing cells become dysfunctional, you will not be able to produce enough to keep your blood glucose levels normal and you will develop diabetes.

A family history of the disease is an important risk factor. Fortunately, you can lower your risk by exercising regularly. Working out will help you to normalise your glucose metabolism, as during exercise your muscles can take up glucose without insulin. It will also help you to keep your weight under control and reduce your risk of cardiovascular disease, which is diabetes’ major complication. Exercise is therefore a cornerstone of the prevention as well as of the treatment.

As exercise is so important for people at risk, the obvious question is: do people with and without a family history have different aptitudes for sport? To answer this, Antonio Bianco and his colleagues compared the aptitude for anaerobic performance of 33 elite athletes without a family history of type 2 diabetes with 13 elites with a family history.

The anaerobic metabolism is the pathway to produce energy without oxygen, as opposed to the aerobic metabolism. It is much quicker, but it is less economical than the aerobic metabolism, and your body will therefore use it for short, high intensity activities such as high intensity interval training and strength exercise.

The athletes performed squat jumps and a Wingate test*, which is the classical test to determine somebody’s peak anaerobic power.

As suspected, the athletes with a family history had a higher body mass than the others, but, surprisingly, their anaerobic performances were significantly better.

The majority of the studies showing the importance of regular workouts for diabetes used aerobic exercise. However, a mounting amount of evidence suggests that strength exercise is just as beneficial. If Bianco is right, his findings would be important for everybody who has a family history of type 2 diabetes, since it is likely that you will prefer an exercise discipline you are good at.

In other words: if you have a family history of type 2 diabetes, you might be better at sports that include shorter period of intense activity and/or power (e.g. most ball sports, gym work) than at endurance sports (e.g. distance running, walking). Maybe you would you therefore prefer them?

The most important thing is that you love your chosen form of exercise so much that you keep doing it!

*A Wingate test is performed on a specialised ergometer. After warming-up, the athlete starts pedalling as fast as possible. After three seconds the researcher adds a resistance corresponding to 75g/Kg of the athlete’s weight to the flywheel. The athlete continues to go as hard as possible for 30 seconds, and the researcher notes the peak power output.

Disclaimer: If you are new to exercising, please ask your doctor for advice first.This article is for general information only, and does not replace medical advice. It cannot be used to diagnose or guide treatment. If you have any concerns or questions, you should talk to a qualified health provider.

References and further reading:

A Bianco, F Pomara, M Raccuglia et al. The relationship between type 2 diabetes family history, body composition and blood basal glycemia in sedentary people. Acta Diabetol. 2014; 51(1): 79-84.

A Bianco, F Pomara, A Patti et al. The surprising influence of family history to type 2 diabetes on anaerobic performance of young male elite athletes. Springerplus. 2014; 3: 224. doi: 10.1186/2193-1801-3-224. eCollection 2014.

R Khardori, G T Griffing, B E Brenner et al. Type 2 Diabetes Mellitus. Medscape (Accessed on 5/10/2014).

R J Wood and E C O’Neill. Resistance training in type II diabetes mellitus: impact on areas of metabolic dysfunction in skeletal muscle and potential impact on bone. J Nutr Metab. 2012; doi:10.1155/2012/268197.  (Accessed on 5/10/2014).

Sleep enough to keep slim

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© Peter Elvidge | Dreamstime Stock Photos

 More and more people are overweight or obese and at the same time more and more people do not sleep enough. Could there be a link? Scientists have studied this problem by asking participants to reduce their sleep, usually from 8.5h/day to 5.5 h/day. They then noted what and how much the participants ate, and measured any hormone or body weight changes. Most of them would now answer yes indeed, there is a link.

It is clear that nobody believes that you can sleep excess weight off, but not sleeping enough (less than 7 hours/day) can hamper your efforts to slim down or keep your weight under control.

At a first glance this looks unbelievable, as when you are awake for longer, you are going to spend more energy.

The energy you spend consists of 3 components:

1) what you need to keep your body going (your basic metabolic rate),

2) the amount needed to assimilate food,

3) the energy used for all kinds of exercise and activities.

When asleep, you will not eat or move and your basic metabolic rate is reduced by 20-30%. Scientists have calculated that sleeping 5.3h instead of 8h would increase the amount of energy you spend by 45 kcal/d.

However, it is here that your unconscious brain starts interfering. As we have seen in some previous posts (e.g. here or here), your brain wants to keep you safe and it therefore wants your energy balance to remain the same. The balance between the energy you take in and the energy you spend determines your body weight, and depends on genetic, psychological and behavioural factors. Even if it sets your body weight a bit too high for your health, your brain will be unwilling to change it, as anybody who has ever tried to lose weight knows only too well.

Experiments have shown that when you have not slept enough, your brain will stimulate you to eat more to compensate for the energy you have spent. Unfortunately, it will make you overdo it. It will do so by making food more rewarding, and the data show that you will tend to snack more and to choose more fatty and carbohydrate-rich food. This is easily done in our modern world where food is widely available.

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© Remigiusz Oprzadek | Dreamstime Stock Photos

It is easy to see how all this will put your best efforts to stay slim in jeopardy. Moreover, a study by Arlet Nedeltcheva showed that dieters who slept for only 5.5 h/day lost more lean body mass and less fat than dieters who slept for 8.5h. They also suffered more from hunger.

Researchers have also studied the effect of insufficient sleep on next day’s activities. Even though some of them have not observed any effect, most report more sedentary time and less vigorous workouts. The discrepancy might be due to the fact that some study participants were used to insufficient sleep, or to the short duration of some studies which could not capture the full effect on people who exercise a few times a week.

There are still plenty of questions to be answered, e.g. what is the effect of habit, is there a difference between men and women, is what scientists observe in a study the same as what happens in real life etc…We do not know either what the effect of physical exercise is: regular exercise improves your sleep, which would then influence your energy balance. Nevertheless, it is a good idea to make sure you have enough sleep!

 

References

JP Chaput and MP St-Onge. Increased food intake by insufficient sleep in humans: are we jumping the gun on the hormonal explanation? Front Endocrinol (Lausanne). 2014; Jul 15;5:116. doi: 10.3389/fendo.2014.00116. eCollection 2014 (accessed 26/08/2014).

A V Nedeltcheva, J M Kilkus J Imperial et al. Insufficient sleep undermines dietary efforts to reduce adiposity. Ann Intern Med. 2010; 153(7): 435-441.

P D Penev. Update on energy homeostasis and insufficient sleep. J Clin Endocrinol. Metab. 2012; 97(6): 1792-1801.

MP St-Onge. The role of sleep duration in the regulation of energy balance: effects on energy intakes and expenditure. J Clin Sleep Med. 2013; 9(1): 73-80.

What should we eat?

If you want to create an animated discussion, start talking about what you should eat (or not) to protect yourself from cancer, cardiovascular disease, diabetes etc… Humans have been wondering which foods to eat since ancient times, but we still have more questions than answers!

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© Skdesign | Dreamstime Stock Photos

Several large studies have shown that we should avoid excess calories, eat plenty of fruit and vegetables, reduce the amount of refined sugars and stay away from processed food, but everything else is still open for discussion. Why is this so?

Nutritional science is based on epidemiological studies, from which researchers try to determine what the effects of different foods or diets are. They can then perform interventional studies, whereby they ask half of the study participants to have more of a specific food or change their diet, and compare the effects with the other half of the participants (= the control group). In the Predimed Study for example, researchers examined the importance of olive oil and nuts in this way. Without good epidemiological studies however, researchers do not know what to look for.

I have just stumbled upon an article by Farin Kamangar and Parisa Karimi explaining how difficult it is to conduct such epidemiological studies, and here comes their list of possible errors and problems.

Measurement errors

The first problem Kamangar and Karimi mention is the way they obtain information about what you are eating. Traditionally this is done via questionnaires and interviews assessing your dietary habits over one year. It is clear that it is difficult to recall accurately what you have eaten over a year. Moreover, you might have changed your diet, and what you have eaten last year is therefore not necessarily reflecting your lifelong habits.

Some researchers ask you to write down what you have eaten for the last 24 hours. Even though you will be able to recall this accurately, it is not sure that you are having something similar each day.

Most questionnaires are really long (80 to 200 items), which can discourage even the most motivated participant.

These problems will hopefully be minimised in the future, as researchers are starting to use online self-assessment questionnaires.

Confounders

Epidemiologists try to find an association between risk factors and diseases. Confounders are factors that independently affect the risk of developing the disease, and therefore falsify the results of the study.

A classical example is the association between coffee drinking and lung cancer. Previous studies suggested this, but as coffee drinkers were more likely to be cigarette smokers, the risk of developing lung cancer had nothing to do with coffee. Another example is the association between lying in bed and dying. As most people die in bed, you would conclude that beds are the most dangerous places on earth.

As confounders are usually unknown, it is easy to see how they can falsify the results. Researchers try to avoid them by comparing populations that are very similar except for the factor they want to study. With this in mind, Beth Taylor and her colleagues compared marathon runners with their non-competitive spouses to examine the effect of strenuous exercise on your arteries.

Variability of food products

Foods are typically grown and/or prepared in different ways in different parts of the world, which might affect their nutritional value. Kamangar and Karimi cite the example of brown rice, which is a healthier choice than white rice since it contains more fibre, but in the United States it has a higher arsenic concentration than white rice. Another example is the difference between grass-fed and grain-fed beef: grass feeding typically results in leaner meat.

The correct control group

As already mentioned above, finding a good control group is a challenge: it has to resemble the study group except for the factor the researchers want to study.

In nutritional science this is very difficult, as the study participants avoiding a specific food usually replace it by something else. For example, imagine what the study results would be if participants abstaining from a specific, probably unhealthy food use to replace it by something containing plenty of simple sugars.

Interactions

Foods contain chemical substances that influence each other’s absorption and actions, and different foods can contain the same substance in different amounts and availabilities. These interactions are very complex, and researchers need large study groups to try to avoid them.

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© John Valenti | Dreamstime Stock Photos

Multiple testing

Epidemiological studies about nutrition are typically large and expensive. Researchers want to use all the data and they therefore test several hypotheses at once. However, there is always a chance to come to a false conclusion by coincidence. Statistically, the probability to obtain such a false positive result is 20%, which means that if you test 20 hypotheses, you will get at least one false positive one.

And therefore…

Nutritional science is fascinating, but difficult. Keep informed, stay critical and be prepared to change your mind.

References:

F Kamangar and P Karimi. The state of nutritional epidemiology: why we are still unsure of what we should eat? Arch Iran Med. 2013; 16(8):483-486.

BA Taylor, AL Zaleski, JA Capizzi et al. Influence of chronic exercise on carotid atherosclerosis in marathon runners. BMJ Open. 2014; 4(2): e004498. doi: 10.1136/bmjopen-2013-004498.

ME Van Elswijck and SH McNeill. Impact of grass/forage feeding versus grain finishing on beef nutrients and sensory quality: the US experience. Meat Sci. 2014; 96(1):535-40.

 

Extra-virgin olive oil and your health

The Mediterranean diet has been linked to a longer and healthier life, but the reason why is not completely clear yet. It is likely to be due to a multitude of factors, such as plenty of fruit and vegetables, garlic, fish, a more outdoor lifestyle…Olive oil is a key component, and the latest publication from the Predimed study shows that the extra-virgin variety is the most beneficial, suggesting that the effects are mainly due to its phytochemicals.

© Esra Paola Crugnale | Dreamstime Stock Photos
© Esra Paola Crugnale | Dreamstime Stock Photos

We assumed for many years that the benefits of olive oil are due to its high content of mono-unsaturated fatty acids. However, many foods in a typical Western diet contain plenty of mono-unsaturated fatty acids, but do not seem to be as beneficial.

Olive oil also contains many phytochemicals such as polyphenols, phytosterols and vitamin E, which are anti-oxidant and anti-inflammatory. The amount depends on the kind of olive oil: extra-virgin is the first oil obtained by mechanically pressing olives, and contains much more phytochemicals than common or virgin olive oil. If the benefits of olive oil are largely due to its phytochemicals, extra-virgin oil should be much better for you than any other variety.

The Predimed (Prevencion con Dieta Mediterranea) is a Spanish study trying to understand which components of the Mediterranean diet are the most important and why. 7216 older adults at high risk of cardiovascular disease participated, and were randomised in three groups. They all continued with their usual Mediterranean diet, but one group added more olive oil, a second group consumed extra nuts, and the third group reduced the amount of fats. In their latest publication, the researchers looked at the effects of olive oil on cardiovascular disease. (I have blogged about the results concerning nuts previously.)

Sure enough, consuming more olive oil was associated with a reduced risk of cardiovascular disease, but the association was due to the use of extra-virgin olive oil: for each 10g/day more extra-virgin olive oil the risk of having cardiovascular disease was reduced by 10%, and the risk of dying from it by 7%. Using common olive oil did not have any benefits.

The researchers could not find a reduced risk of cancer, but they did not examine specific types of cancer. Other studies however, have shown that olive oil reduces the risk of breast cancer and some digestive and respiratory cancers.

References:

M Guasch-Ferre, F B Hu, M A Martinez et al. Olive oil intake and risk of cardiovascular disease and mortality in the PREDIMED study. BMC Medicine. 2014: 12: 78. doi: 10.1186/1741-7015-12-78. Accessed on 20/05/2014.

E Waterman and B Lockwood. Active components and clinical applications of olive oil. Altern Med Rev. 2007; 12(4): 331-342.

Active kids reduce their risk of cardiovascular disease later in life

We know that atherosclerosis begins in childhood, but are children with an unhealthy lifestyle invariably going to suffer from atherosclerosis as they get older? Nobody is sure…

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© Alexk | Dreamstime Stock Photos

A Finnish group of researchers has therefore started to follow-up risk factors in young people. The first survey was done in 1980, when they examined 3596 youngsters between 3 and 18 year old. The same group was then re-examined in 1983, 1986, 2001 and 2007. The researchers measured the usual risk factors such BMI, blood lipids and blood pressure, and asked about their diet and exercise habits.

In 2001 and 2007, the researchers also determined the wall thickness and elasticity of the youngsters’ arteries. Wall thickness and elasticity (or stiffness) are two different signs of vascular aging, and both of them are probably very early stages of the disease. As yet, we do not know which one is more important.

By comparing the evolution of arterial wall thickness and elasticity with risk factors, we can determine if a child’s lifestyle influences its risk of cardiovascular disease later in life.

Elasticity

In their latest article (April 2014) the Finnish group published their findings concerning the association of exercise in childhood or adolescence and the elasticity of the carotid arteries 21 years later. The carotid arteries are situated in the front of your neck and supply your head and neck with oxygenated blood. They are rather important, as your risk of stroke increases if they narrow due to atherosclerosis!

They noticed that exercise in children and adolescents was associated with an increased arterial elasticity in 30 to 34 year old adults. This was independent of other factors such as BMI, blood lipids or insulin levels. They concluded that it pays off to be an active kid.

Vigorous exercise

This confirms a similar study published in 2010 by Roel van de Laar and his colleagues. They followed 600 boys and girls during 24 years, and noticed that adolescent and young adults involved in vigorous physical exercise had more elastic arteries at the age of 36 than those who performed only easy or moderate workouts.

They also noticed that those who kept exercising vigorously in adulthood had a much better elasticity than those who slowed down. The difference in elasticity went hand in hand with other risk factors such as cholesterol levels, resting heart rate, cardio respiratory fitness…

They concluded that we should keep exercising vigorously as we get older to keep our arteries healthy.

Working Up Sweat (ID: 74747)
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Arterial thickness

The Finnish group also compared the classical risk factors (exercise, diet, BMI, cholesterol, blood pressure blood glucose levels…) with the thickness of the arterial wall. They noticed that childhood risk factors became non-significant compared to adult ones, except for physical activity and fruit consumption.

This means that if somebody has unfavourable cholesterol levels or is obese as a child, but corrects this as an adult, the arterial wall thickness is not worse than that of somebody who was not obese or did not have bad cholesterol levels as a child.

For fruit consumption and physical exercise however, this seems not to be true. Eating a healthy diet and exercising regularly as a child is thus important for your arteries.

What does this mean for me?

If you are lucky enough to have exercised and eaten a healthy diet as a child, your arteries are likely to be healthy. This is not a reason to stop taking care of yourself, as Roel van de Laar’s study shows that we should continue exercising vigorously.

Vigorous exercise is of course different for each of us. What feels like running hard for me is maybe only a jog for you. Only you can know what vigorous exercise is for you. Don’t forget either that nobody exercises vigorously every day. If you are in doubt, you should contact a health or fitness professional.

Even though exercising as an adult might not totally reverse the lack of exercise as a youngster, it will help you to keep all other risk factors under control. Moreover, your health depends on much more than the thickness or elasticity of your arterial walls. Exercise will reduce your risk of many diseases, such as diabetes, Alzheimer and some cancers. It is therefore never too late to start!

The Finnish study is ongoing, and that is a good thing as there are plenty of questions left. For example: what happens to those of us who are active as a child and adolescent,  abandon sport to raise a family, and start training again when life becomes less busy?

Disclaimer: this article is for general information only, and does not replace medical advice. It cannot be used to diagnose or guide treatment. If you have any concerns or questions, you should talk to a qualified health provider.

References:

Juonala M, Viikaril J S A, Kahonen M et al. Life-time risk factors and progression of carotid atherosclerosis in young adults: the cardiovascular risk in young Finns study. Eur Heart J 2010; 31(14): 1745-1751.

Palve KS, Pahkala K, Magnussen CG et al. Association of physical activity in childhood and early adulthood with carotid artery elasticity 21 years later: the cardiovascular risk in young Finns study. J Am. Heart Assoc. 2014; 3(2): e000594.  doi: 10.1161/JAHA.113.000594.

Van de Laar RJ, Ferreira I, van Mechelen W et al. Lifetime vigorous but not light-to-moderate habitual physical activity impacts favorably on carotid stiffness in young adults: the Amsterdam growth and health longitudinal study. Hypertension 2010; 55(1): 33-39.

Choose chewier food to eat less

A mounting amount of evidence shows that eating with smaller bites and keeping your food for longer in your mouth makes you take in fewer calories. However, as all these studies have been done under standardised conditions in labs, it is not clear how you could do this in daily life. How can you keep taking smaller bites and keeping food in your mouth for longer while chatting or watching television?

© Max Blain | Dreamstime Stock Photos
© Max Blain | Dreamstime Stock Photos

In her latest article on the subject, Dieuwerke Bolhuis suggests choosing harder foods, which will need more chewing, to achieve just that without having to think about it.

Bolhuis and her colleagues asked 50 volunteers to have a meal of harder foods and one of softer foods for lunch on two different days. The volunteers ate as much as needed to feel “pleasantly full” while the researchers filmed them to determine their bite size and the time it took them to chew and swallow the food. The volunteers were invited for dinner on the same day as they had lunch. They could again eat as much as needed, and the researchers calculated the amount of energy they were taking in.

Eating harder foods indeed forced the volunteers to take smaller bites and chew longer, and led to a 13% lower energy intake. They did not compensate for this at dinner, which means that had eaten substantially less over the day without noticing any difference.

Click here to see the results as a graph: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3973680/figure/pone-0093370-g002/

If you could keep having about 13% less energy a day, you would quickly lose weight indeed. Moreover, the harder or chewier foods are often the healthier ones as well, as they are likely to be less processed or to contain more fibre. Unfortunately we do not know yet whether this can go on day after day: would your body end up compensating by eating more?

Anyway, it is certainly something to try out.

Disclaimer: this article is for general information only, and does not replace medical advice. It cannot be used to diagnose or guide treatment. If you have any concerns or questions, you should talk to a qualified health provider.

References:

DP Bolhuis, CG Forde, Y Cheng et al. Slow food: sustained impact of harder foods on the reduction in energy intake over the course of the day. PloS One 2014; 9(4): e 93379. doi: 10.1371

Running and cardiovascular disease

Nordea Riga Marathon 2010: 5K race

Experts agree that moderate exercise reduces your risk of cardiovascular disease, but the exact mechanisms are not completely clear. Does it keep your blood vessel healthy, increase the electrical stability of your heart or just improve your metabolism? As endurance athletes are health-conscious, it is not clear either how much of the benefits are due to a healthy lifestyle and how much to exercise.

Moreover, recently some scientists have wondered if strenuous exercise, such as marathon running, could be more harmful than beneficial. I have blogged about this problem before.

To answer all these questions, Beth Taylor and her colleagues have compared the arterial stiffness, carotid artery wall thickness and cardiovascular risk factors (cholesterol, triglycerides, body weight…) between 42 Boston marathon qualifiers and their sedentary spouses.

Arterial wall thickness is a risk factor of cardiovascular disease, as it is probably one of the early stages of atherosclerosis.

There is more and more evidence that there is a relation between arterial stiffness and cardiovascular disease.

Several studies have looked at the influence of strenuous exercise on wall thickness and stiffness before but the results are contradictory, probably because other lifestyle factors, such as diet, are confounding them. As the sedentary partners had the same lifestyle as the runners but only performed moderate workouts, this study isolates the effects of strenuous exercise.

As suspected, the cardiovascular risk factors were better in the runners than in their sedentary partners. The arterial wall thickness and stiffness however, were not different.

The researchers concluded that exercise protects you by other mechanisms than by preventing atherosclerosis. This would then explain why scientists have found a large plaque burden in some runners. On the other hand, it once again shows that strenuous exercise is not bad for you, as the runners did not show an increased arterial wall thickness or stiffness. Hopefully, this will put an end to this lingering debate!

However, marathon running does not make you immune from cardiovascular disease, and you should always take any symptoms seriously.

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One glass of red wine and your health

Could drinking a glass of red wine a day further decrease your risk of cardiovascular disease on top of a healthy lifestyle?

A decanter with a red wine glass

Studies in the 1970’s have shown that people who drink just one glass of red wine a day have a lower risk of cardiovascular disease, but it is not sure if that is also true for people who exercise regularly and adopt a healthy diet. In a study published in Nutrition Journal, Dirk Droste and colleagues investigated just that, and concluded that it remains true indeed.

The researchers divided 108 high-risk patients ad random in two groups. One group adopted a Mediterranean diet and started to exercise regularly, while the other group did not change their lifestyle at all. Each group was again divided in two, and one half added daily a small amount of red wine to their diet (0.2 L for men and 0.1L for women) and the other half abstained from all alcohol. The researchers obtained therefore 4 groups:

1)      patients adopting lifestyle changes and drinking one glass of red wine

2)      patients not changing their lifestyle and drinking one glass of red wine

3)      patients adopting lifestyle changes and not drinking any alcohol

4)      patient not changing their lifestyle and not drinking any alcohol

They followed all the patients by measuring blood lipids, such as low density protein (LDL or the “bad” cholesterol) and high density protein (HDL, the “good” cholesterol), since these are well known risk factors for cardiovascular disease. After 20 weeks, lifestyle changes improved the ratio LDL/HDL by an average of 8% and red wine by an average of 13% (!). Moreover, the effect of red wine was independent of the lifestyle changes; in other words: there was an additional benefit, even though the effect of red wine was more remarkable in those who did not change their lifestyle. Even patients taking statins showed improvements.

Why red wine?

Red wine is one of the richest sources of polyphenols in the human diet. Polyphenols are powerful anti-oxidants which come from the skins, seeds and stems of grapes. The strongest and best known is resveratrol, but the amount in just one glass of red wine is probably not enough to have any effect.

Several studies have shown that alcohol can be good for your health if you drink it in moderation (a maximum of 1 drink or 12.5g alcohol a day for women and 2 drinks or 25 g alcohol a day for men). It increases HDL, is anti-inflammatory, and helps to prevent clot formation and to control glucose levels. More and more scientists now think that the health benefits of red wine are simply linked to a daily light consumption of alcohol and not to resveratrol. Consequently, scientists have tried to find out if beer can be just as beneficial as wine, but studies are  contradicting.

Do not drink too much!

Alcohol increases your risk of high blood pressure, stroke, liver disease and various tumours, such as breast and colorectal cancer. Even small amounts increase your risk of cancer, as there is no “safe” dose and light drinking does not protect you at all in this case. Overconsumption leads to violence and accidents. The end result is a J-shaped relationship between alcohol and overall mortality, whereby light drinking increases your chances of a long life and heavy drinking reduces it.

No Alcoholic Beverages
No Alcoholic Beverages (Photo credit: Travis S.)

What does it mean for me?

Nobody will advise you to drink alcohol to improve cholesterol levels, because the dangers linked to overconsumption are too important. It is indeed impossible to know in advance who is going to be able to remain a daily light drinker and who is not.

If you do not drink alcohol, do not start, as the risks are too large. However, if you use alcohol, try to limit your consumption to 1(women) or 2 (men) units a day.

Disclaimer: this article is for general information only, and does not replace medical advice. It cannot be used to diagnose or guide treatment. If you have any concerns or questions, you should talk to a qualified health provider

References:

D Droste, C Iliescu, M Vaillant et al. A daily glass of red wine associated with lifestyle changes independently improves blood lipids in patients with carotid arteriosclerosis: results from a randomized trial. Nutrition Journal 2013; 12: 147. doi: 10.1186/1475-2891-12-147.

J O’Keefe, K Bybee and C Lavie. Alcohol and cardiovascular health: the razor-sharp double-edged sword. JACC 2007; 50(11): 1009.

P Ronsky, S Brien, B Turner et al. Association of alcohol consumption with selected cardiovascular disease outcomes: a systematic review and meta-analysis. BMJ 2011; 22: 342. doi: 10.1136/bmj.d671.