Tag Archives: Cardiovascular disease

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.

Picture:

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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…

© Alexk | Dreamstime Stock Photos
© 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)
© Vlad | Dreamstime Stock Photos

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.

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.

Fats, carbohydrates and how to keep your heart healthy

A breakfast very high in saturated fat

Saturated fat from your diet increases your LDL and total cholesterol, but stating that this puts you at an increased risk of cardiovascular disease, as we have done for many years, is too simplistic.

Most fats in your food and in your body are triglycerides, which consist of 3 fatty acids. Whether these fatty acids are saturated or unsaturated varies with your diet, as triglycerides can be made up of fats that you have eaten or fats made by your liver from other energy sources such as carbohydrates.

Cholesterol is another kind of fat that you can get from food or produced by your liver.

As fat cannot dissolve in blood, most of it is moved around your body in small particles, called lipoproteins. The most important ones are the low density lipoproteins (LDL) and the high density lipoproteins (HDL). LDL carries cholesterol and fat from the liver to the rest of your body, where they are needed by your cells for energy production and to make essential substances such as hormones. HDL picks up the surplus of LDL from your blood and brings it back to your liver.

Atherosclerosis

How exactly atherosclerosis plaques develop is still not well understood, but as far as we know LDL particles get trapped in the vessel wall, where they become oxidized by free radicals. This creates an inflammatory reaction which leads eventually to the formation of a plaque.

Too much saturated fat in your blood can also cause an inflammatory reaction, and can therefore start and/or aggravate the situation.

Studies have shown that too much low density lipoprotein or LDL puts you at a higher risk of cardiovascular disease, and that high density lipoprotein or HDL protects you. LDL is therefore often called “bad” cholesterol and HDL “good” cholesterol, and clinicians use the LDL/HDL ratio or the total cholesterol/HDL ratio to estimate your risk. The amount of triglycerides in your blood is also important.

To keep your vessels healthy, you want a diet that is anti-oxidant and anti-inflammatory, improves the LDL/HDL ratio and lowers the amount of triglycerides.

Trans-fats

Everybody agrees that industrial trans-fats are bad for your health. They are made by hydrogenating vegetable oils and, as they are more stable than other fats, are ideal for frying and making processed food. However, they increase LDL and lower HDL, and you should therefore avoid them. Some whole foods such as milk contain small amounts of trans-fats, but there is evidence that these are different from the industrial ones and do not harm you.

Salers Cow. Milk and meat from cows and other ...
Salers Cow. Milk and meat from cows and other ruminants contains naturally occurring trans fats in small quantities (Photo credit: Wikipedia)

Saturated fats

Saturated fats are typically found in red and processed meat, butter and other forms of animal fats. Previously, scientists thought that eating too much saturated fats increases your risk of cardiovascular disease, as they raise your LDL. However, studies do not confirm this.

Their effects on your health vary depending on which food they come from. Red meat contains cholesterol and heme iron that probably increase the risk, and processed meats contain preservatives that are bad for your health. Milk and milk products on the other hand, are a good source of nutrients such as calcium, potassium, phosphorus and vitamin D. As a result, they lower your risk of cardiovascular disease.

Different foods contain different proportions of specific saturated fats, combined or not with other fats, and affect therefore your risk factors in different ways. Unfortunately, we do not understand this fully yet and we need more research.

Most scientists agree that you should try to limit your intake to about 10% of your energy, but it is very controversial that limiting it even further is helpful. Moreover, an important question is by what you replace it.

Mono-and poly unsaturated fats

Replacing saturated fats by mono-unsaturated fats improves the LDL/HDL ratio slightly. A Mediterranean diet is good for your heart and blood vessels, but modern studies could not proof that this was due to its high mono-unsaturated fat content.

Many studies have shown that replacing saturated fats by polyunsaturated fats is beneficial. Unfortunately, they did not differentiate between trans-fats and saturated fats and some scientists think that the beneficial effects were due to the fact that the trans-fats were taken out of the diet, and had nothing to do with reducing the saturated fats.

This is a controversial and rapidly evolving subject, and it is therefore a good idea to keep informed about the latest findings. As yet, it is prudent to reduce the amount of saturated fats in your diet to about 10%, and to favour polyunsaturated fats.

Sources of mono-unsaturated fat include nuts, olives, vegetable oils and avocados, but also beef and milk. You will find polyunsaturated fats in food such as seeds, nuts and fish.

Carbohydrates

In practice, fats are often replaced by carbohydrates. Unfortunately, this increases the risk of cardiovascular disease, because your liver transforms the surplus of carbohydrates into saturated fats. These interact then with your immune system, which leads to a chronic, low-level inflammation and stimulates the formation of atherosclerotic plaques.

The situation is especially bad when you are eating high glycemic index foods.

The glycemic index ranks carbohydrate-containing foods according to how quickly they increase the glucose levels in your blood. Foods such as white bread, pretzels or sugary drinks are high glycemic, as they have a score of more than 70, while carrots, lentils or apples are low glycemic (their score is less than 55). You can find lists in books or online, for example here.

We should therefore reduce the amount of carbohydrates with a high glycemic index, eliminate industrial trans-fats from our diet and consume more vegetables, fruit and fish.

Saturated fats are not the only cause of chronic inflammation: sleep deprivation, smoking, inactivity and stress are also important factors. It is not enough to have a healthy diet; you need to have a healthy lifestyle.

English: vegetablesDisclaimer: 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:

M de Oliveira Otto, D Mozaffarian, D Kromhout et all. Dietary intake of saturated fat by food source and incident cardiovascular disease: the multi-ethnic study of atherosclerosis. Am J Clin Nutr. 2012; 96(2): 397-404.

R Kuipers, D de Graaf, M Luxwolda et al. Saturated fat, carbohydrates and cardiovascular disease. Neth J Med. 2011; 69(9): 372-378.

K Kingsbury and G Bondy. Understanding the essentials of blood lipid metabolism. www. medscape. com; accessed 13/10/2013.