Disappointing news – or not – about moderate drinking

heart

Many studies and reviews have supported the notion that moderate alcohol consumption is beneficial for heart health. Why not have a daily glass or two of wine at dinner, as it could ward off disease. And now they come and spoil the fun.

A joint group of Canadian, Australian and US scientists took a hard look at the evidence presented in previously published research and found little support for a heart protective effect of moderate alcohol consumption.

And here you are believing the previously good news, who can you really trust? But not all is lost so read on.

So what did they find?

The new assessment initially agreed with the previous findings as a fully adjusted pooled analysis of all the 45 studies reviewed found significantly reduced coronary heart disease mortality for current moderate drinkers, actually for all current drinkers.  So all good now, can I continue to have a glass or two of wine to dinner and feel healthier?

Unfortunately not, as the researchers found confounding factors in that they could see an influence of age, gender, ethnicity, and heart health at baseline. When correcting for such factors they claim that moderate consumption of alcohol was not significantly protective for people at ages 55 years or younger at baseline, or for studies controlled for heart health at the beginning of the study. They even claimed that the appearance of cardio-protection among older people may reflect systematic selection biases that accumulate over the life course.

Their hypothesis is that non-drinkers may, in fact, be former drinkers who quit or cut down for health reasons. So, of course the remaining healthy drinkers will fair better than their poor abstainers that are already sick. And the seniors who are healthy may be more likely to keep enjoying that glass of wine with dinner thus biasing the results.

However, the researchers stop short of turning the previous findings on its head. They only conclude that there remain grounds for skepticism about the hypothesis that alcohol use can be cardio-protective, and recommend that future prospective studies not only avoid biased abstainer reference groups, but also take steps to minimize other forms of selection bias across the life course, including that from competing disease risks.

So there is still hope?

red_wine_(boo_licious)Yes, there is still hope that a daily glass of wine might keep you healthy longer as the researchers can’t prove it one way or the other. Only that there are grounds for a healthy skepticism as there remain plausible alternative explanations for their observed review findings.

So let’s make it clear. For now, no one is saying that people who enjoy alcohol in moderation should stop. Should there be no direct benefits, at least the risks of low-level drinking would be small.

Let’s drink to that, but only in moderation!

Purple is the new green

Why not purple broccoli (Photo: AJC)

Why not purple broccoli… (Photo: AJC)

The constant nagging of children to eat their greens often has little effect. But have you ever heard parents urge their children to eat their purples. I didn’t think so, but they probably should. In flowers, bright red and purple colours are used to attract pollinators. In fruits, the colorful skins also attract the attention of animals, which may eat the fruits and disperse the seeds.

If that holds true for children it could be a way of making fruit and vegetables more attractive. And thus encourage increased consumption to reach the goal of 400 g a day set by the World Health Organization. It is clear that there are considerable benefits in increasing consumption of fruit and vegetables for most of us. In many parts of the world, fruit and vegetable consumption is dismal.

But what about health aspects of the purple colour itself?

No lack of praise of purple foods

First you need to know that the colour is caused by anthocyanins that are water-soluble pigments belonging to a parent class of molecules called flavonoids. They may appear red, purple, or blue depending on the pH. Anthocyanins are powerful antioxidants and there is no lack of praise of purple fruit and vegetables on the web. Just a few examples:

  1. The top benefactor in purple foods is their antioxidant content. The powerful health benefits of antioxidants are only too well known: they neutralise the agents of aging and disease, and keep you looking younger longer.
  2. A basket filled with luscious blue or dark red fruit and vegetables does much more than look good in still life paintings or on your kitchen counter. It contains a wealth of incredible health benefits.
  3. There is evidence that purple foods improve heart health, vision, and brain power. Recent studies found that adults who eat purple and blue fruits and vegetables have reduced risk for both high blood pressure and low HDL cholesterol; they are also less likely to be overweight.
  4. Let’s take a deeper look into these dark nutritional superheroes. Here are five reasons to eat more purple foods: purple foods kill cancer, are ulcer-fighters, are good for your liver and heart, and prevent urinary tract infections.

Convinced? Not so fast. Vegetables and fruits are rich sources of antioxidants. There is good evidence that eating a diet with lots of fruits and vegetables is healthy and lowers risks of certain diseases. But it isn’t clear whether this is because of the antioxidants, something else in the foods, or other factors.

So what are antioxidants?

... or purple carrots ...

… or purple carrots …

Antioxidants are man-made or natural substances that may prevent or delay some types of cell damage by counteracting oxidative stress. Free radicals can cause oxidative stress, a process that can trigger the cell damage. Free radicals are highly unstable molecules that are formed during exercise and conversion of food into energy or can be accumulated from a variety of environmental sources, such as cigarette smoke, air pollution, and sunlight. Oxidative stress is thought to play a role in a variety of diseases including cancer, cardiovascular diseases, diabetes, Alzheimer’s disease, Parkinson’s disease, and eye diseases such as cataracts and age-related macular degeneration.

Antioxidants are found in many foods, including fruits and vegetables. They are also available as dietary supplements. Examples of antioxidants include vitamins C and E, selenium, and carotenoids, such as beta-carotene, lycopene, lutein, and zeaxanthin. As well as flavonoids, like the purple anthocyanins.

The flavonoids have long been thought to be nutritionally important for their antioxidant activity, but actually have little or no value in that role. Unfortunately, research has now proven that flavonoids are poorly absorbed by the body, usually less than five percent, and most of what does get absorbed into the blood stream is rapidly metabolised in the intestines and liver and excreted from the body.

But don’t give up yet!

Anthocyanins may indeed benefit human health, but for quite different reasons. The body sees them as foreign compounds  and through different mechanisms, they could play a role in preventing cancer or heart disease. They appear to strongly influence cell signaling pathways and gene expression, with relevance to both cancer and heart disease. A relatively modest intake – like the amount found in five to nine servings of fruits and vegetables – is sufficient to trigger a much larger metabolic response.

Flavonoids also increase the activation of existing nitric oxide synthase, which has the effect of keeping blood vessels healthy and relaxed, preventing inflammation, and lowering blood pressure – all key goals in prevention of heart disease.

Both of these protective mechanisms could be long-lasting compared to antioxidants, which are more readily used up during their free radical scavenging activity and require constant replenishment through diet.

So why not go for purple foods

... or spiff it up with a purple spud.

… or spiff it up with a purple spud.

So not too bad after all. Beetroot and eggplant have long been obvious choices, and of course all the berries. But now there are also purple carrots, cabbage, potatoes, onions, sweet potato, maize and asparagus.

The ancestors of the carrot can be traced back to Iran and Afghanistan, and the original carrots were predominantly purple. It was only during the 17th century that western Europeans began cultivating orange carrots.

The purple sweet potato has only been available commercially since 2006, after a North Carolina sweet potato farmer received some as a gift and began to cultivate them on a large scale.

The vividly colored cauliflower variety was achieved after painstaking cross breeding and has a similar flavor to its white cousin.

The purple-black maize is commonly grown in the Andes Mountains and is a popular food in Bolivia, Ecuador, Mexico, and Peru.

Purple kale is cultivated from the dwarf variety of kale, and adds a splash of color to green salads. Like green kale, it has a cabbage-like flavor and a slightly chewy texture.

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Survival of the fishiest

Daily cod liver oil of the past (Credit:

Daily cod liver oil of the past (Credit: Caroline)

I was brought up on a spoonful of cod liver oil a day, not sure if that did any good at the time though. I remember I didn’t like it, not that I had much of a say. I have since resisted all overtures to take a daily omega-3 fish oil capsule, although I have praised them in previous blog posts. The science seemed to be clear, omega-3 fatty acid supplements looked to be one of the few supplements with a real health benefit. Now I take all this back.

I know, nutritional science is confusing and nutritionists seem to change their recommendations regularly. One day a green capsule a day of some obscure substance is a must and a red tablet should be avoided. The next day it is the opposite. What is an ordinary person to do? Well, at least it creates more work for nutritionists (and EFSA’s Panel on Dietetic Products, Nutrition and Allergies) and some fodder for sensationalising newspaper articles.

Eskimo diet hypothesis proven wrong

As it happens, the current recommendation to eat more oily fish as part of a heart healthy diet has mainly been based on a landmark study from the 1970s by two Danish investigators, Bang and Dyerberg. They had been told that the Greenland Eskimos had a low prevalence of coronary artery disease and set out to study their diet. They described the Eskimo diet as consisting of large amounts of seal and whale blubber (i.e. fats of marine animal origin) and suggested that this diet was a key factor in the alleged low incidence of coronary heart disease. This started an avalanche of studies that focused on the cardioprotective effects of the Eskimo diet and created an industry around fish oil supplements containing omega-3 fatty acids.

Building on 40 years of new research since the Danish findings, a team of scientists recently conducted a review of the resulting literature to examine whether mortality and morbidity due to coronary artery disease are indeed lower in the Eskimo population compared to their Caucasian counterparts. Most studies reported that the Greenland Eskimos as well as the Canadian and Alaskan Inuit had coronary artery disease as often as the non-Eskimo/Inuit populations.

Unfortunately, Bang and Dyerberg’s studies from the 1970s failed to actually investigate the cardiovascular health of the the Eskimo population, and as a result the cardioprotective effects of their dietary findings were unsubstantiated. They rather relied on annual reports produced by the Chief Medical Officer of Greenland covering cardiovascular deaths in the region. Because of the rural and inaccessible nature of Greenland, it was difficult to keep accurate records of cardiovascular disease affecting the population and the validity of Greenland’s death certificates have been questioned. Actually, 20% of the death certificates were  even completed without a doctor examining the body.

Use of omega-3 fatty acids ambiguous

Enjoy the real thing (Photo: Renée Suen)

Enjoy the real thing (Photo: Renée Suen)

The new review did not only show that the Eskimos and Inuits have a similar prevalence of coronary artery disease to the rest of the population, but in fact have very high rates of mortality due to stroke. Overall, their life expectancy is approximately 10 years less than the typical Danish population.  It is thus remarkable that instead of labelling their diet as dangerous to health, it was proposed that dietary intake of marine fats prevents coronary arterial disease and reduces atherosclerotic burden.

It is clear that many recent large and well-designed studies have shown ambiguous or negative results regarding the cardioprotective properties of omega-3 fatty acids and fish oil supplements, and yet they are still widely recommended as part of a heart healthy diet plan, supporting a billion dollar industry selling fish oil capsules based on a hypothesis that was questionable from the beginning.

I know what I will do. I will continue to stay away from fish oil capsules, but keep eating my weekly salmon or herring meals because I enjoy them.

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Time for some dark chocolate indulgence

Eating dark chocolate is good for health (Photo: Boz Bros)

Eating dark chocolate can be good for your health (Photo: Boz Bros)

No surprise here, it has been known for quite some time that consuming dark chocolate can improve your health. Mind you, I am not talking about binge eating, but a decent although slightly restrained consumption. Previous research has linked chocolate consumption to many health benefits. One study has suggested that drinking two cups of hot chocolate a day may prevent memory decline, while another study found that eating moderate amounts of chocolate could reduce the risk of stroke.

Just in are new results from a further study of dark chocolate consumption. It seems to be a popular topic creating lots of publicity. And this time it is not results from another correlation study of epidemiological findings or an animal study, but results from a real trial on real people. It might seem too good to be true, but dark chocolate is actually good for you and scientists managed to find out why.

Study design

The scientists selected 44 middle-aged overweight men for the trial. Over two periods of four weeks, the men were required to eat either 70 g of regular dark chocolate each day or 70 g of specially produced dark chocolate with high levels of flavanols – naturally occurring antioxidants found in some plants, including the cocoa plant. Both chocolates were similar in their cocoa content.

Before and after both intervention periods, researchers performed a variety of measurements that are important indicators of vascular health. Scientists also evaluated the sensory properties of the high flavanol chocolate and the regular chocolate and collected the motivation scores of the participants to eat these chocolates during the intervention. As if that would be needed.

During the study, participants were advised to refrain from certain energy dense food products to prevent further weight gain. Too much chocolate can be fattening and they were already quite corpulent.

The findings of the trial

In the randomised double-blind crossover study, the scientists found that eating dark chocolate lowered the augmentation index, a key vascular health predictor, and reduced leukocyte adhesion marker expression.

Hrmm, all fine then, but what does it all mean? And here is the good news. Dark chocolate helps restore flexibility to arteries while also preventing white blood cells from sticking to the walls of blood vessels. That’s huge news when it comes to heart health; both arterial stiffness and white blood cell adhesion are known factors that play a significant role in atherosclerosis – thickening and hardening of the arteries.

Scientists destroying dark chocolate indulgence (Photo: Military Health)

Scientists replacing dark chocolate indulgence with pill (Photo: Military Health)

What’s more, the researchers found that although the chocolate higher in flavanols increased sensory stimulation in participants, both types of chocolate produced the same heart benefits. That’s a challenge to previous research that has suggested that the health benefits from consuming chocolate, wine and berries are due to their flavanol content.

Eat dark chocolate while you can

So the dark side of chocolate is a healthy one. But typical for scientists they said that the effect that dark chocolate has on our bodies is encouraging not only because it allows us to indulge with less guilt, but also because it could lead the way to therapies that do the same thing as dark chocolate but with better and more consistent results. So they still want to deprive us of chocolate indulgence despite its beneficial effect.

Until the dark chocolate drug is developed, eat while there still is time!

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