I’d love to believe

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Red wine benefits?

I’d love to believe that the resveratrol in red wine possesses a range of health benefits including anti-cancer effects, anti-inflammatory effects, cardiovascular benefits, anti-diabetes potential and protection against Alzheimer’s. Thus good for all adult ages. A glass of wine a day might keep the doctor away.

But it might be wishful thinking. It is true that resveratrol can inhibit growth of cancer cells in a culture and in some animal models, but it is not known whether it can prevent cancer in humans. It has increased the lifespans of yeast, worms, fruit flies, fish, and mice fed a high-calorie diet, but again this has not been shown in humans. So the brutal truth is probably that the amount of resveratrol in red wine is too small to have any measurable beneficial effects in humans.

But we can still believe!

whiskybottle

Whisky benefits?

I’d love to believe that the ellagic acid content of whisky actually can reduce oxidative stress. Ellagic acid has been shown to have antiproliferative and antioxidant properties in a number of in vitro and small-animal models. It may directly inhibit the DNA binding of certain carcinogens, and it has a chemoprotective effect in cellular models.

But again it might be too good to be true. Ellagic acid has been marketed as a dietary supplement with a range of claimed benefits against cancer, heart disease, and other medical problems. In 2008, the U.S. Food and Drug Administration called it a fake cancer ‘cure’ consumers should avoid. So not much luck there.

But we can still believe!

It might actually be premature to give up red wine and whisky completely. As antioxidants, like resveratrol and ellagic acid, are additive any contribution is useful. Complement the spirits with plenty of berries, dark green vegetables and nuts and you will not go wrong. Red wine and whisky will be outdone on the health front, but so what.

But there is more…

chilipeppers

Red chilli pepper benefits?

I’d also very much love to believe the latest reports that consumption of hot red chilli peppers can reduce deaths due to heart disease or stroke. Going back for centuries, peppers and spices have been thought to be beneficial in the treatment of many diseases. A new study using National Health and Nutritional Examination Survey (NHANES) III data collected from more than 16,000 Americans who were followed for up to 23 years, found that hot red chilli pepper consumption decreased mortality by 13%.

But unfortunately the findings, widely published by the popular press, are based solely on epidemiological data. Exploring epidemiological data, even if prospective in nature, is fraught with obstacles. The authors themselves point out that given the observational nature of the investigation, causality can only be suggested, not confirmed.

However, on the bright side there is some support for the findings in a theory that capsaicin in chilli peppers can influence cellular and molecular mechanisms that prevent obesity and modulate coronary blood flow, and also possesses antimicrobial properties that may alter the gut microbiota.

In a sign of our desperate need to find some beneficial news the popular press was inundated by citations of the positive findings. Some examples:

  • “Can eating spicy food lead to a longer life? Chili peppers could be the secret” says National Post.
  • “Spicy food could be the secret to a healthy heart and a longer life, says new study” says The Telegraph.
  • “This Is Your Body On Spicy Foods” says The Huffington Post.
  • “Eat Peppers, Live Longer?” says New York Times.
  • “Red hot chilli peppers: the way to a longer life?” says The Sydney Morning Herald.

If you’re on to a good thing the press will pick it up. Doesn’t mean it’s true though. But we can still believe!

Magical dietary fibres

hamburger_(Tony_Evans)

Dietary fibre can influence appetite (Photo: Tony Evans).

We have all heard the “eat more fibre” mantra and wondered what this is all about. So did scientists. Sure we have long known it is good for gut health and function. Recently with the exploration of the gut microbes – the microbiota – we have learnt that dietary fibre can support survival and growth of the good bugs. That we have written about before.

Now scientists have found another piece of the puzzle. Some of the fermentation products produced by the gut microbes from the dietary fibre that our own enzymes cannot digest have the potential to influence our appetite. That is incredible and provides a further insight into the obesity conundrum.

The new mechanism

Obesity is currently one of the most serious global threats to human health. Susceptibility to obesity is determined by genetic background, diet, and lifestyle. Now it has become apparent that the resident intestinal microbes in the large intestine also play an important role.  During the process of microbial fermentation of non-digestible fibre, the short-chain fatty acids acetate, propionate and butyrate are formed.

While short-chain fatty acids can serve as an energy source, the scientists showed that they also act as signaling molecules for the free fatty acid receptor 2 (FFAR2) found in enteroendocrine L cells in the large intestine. These specialised gut cells secrete the appetite suppressing hormone peptide YY (PYY). FFAR2 signaling was found to drive an expansion of the PYY cell population within the large intestine, leading to increased circulating PYY. This is associated with a reduction in food intake and protection against diet-induced obesity.

Evidence points to the production of short-chain fatty acids by the gut microbiota as an important appetite regulatory signal.

So what are fibres?

almonds

Almonds are good sources of dietary fibre.

Just to be clear, dietary fibre is the indigestible portion of food derived from plants. Chemically, dietary fibre consists of non-starch polysaccharides such as arabinoxylans, cellulose, and many other plant components such as resistant starch, resistant dextrins, inulin, lignin, chitins, pectins, beta-glucans, and oligosaccharides. Food sources of dietary fibre are often divided according to whether they provide predominantly soluble or insoluble fibre.

Soluble fibre is found in varying quantities in all plant foods, including in a range of legumes, in oats, rye, chia, and barley, in several fruits, in vegetables, in root tubers and in nuts, with almonds being the highest in dietary fibre.

Sources of insoluble fiber include whole grain foods, wheat and corn bran, legumes such as beans and peas, nuts and seeds and vegetables such as green beans, cauliflower, zucchini and celery.

So there you have a wide variety of healthy foods with the potential of reducing your hunger pangs and alleviate the risk of overweight and obesity.

More dietary fibre

microbiomeniaid

Beneficial bugs (Photo: NIAID)

Be kind to your intestinal flora and it will be kind to you in return. We are talking about the microbiome, the trillions of bugs in your large intestine living in symbiosis with you.

We have written about the microbiome before. All the good deeds the bugs can do if you just feed them the right raw material. And dietary fibre is the ideal food source to support the needs of the beneficial bugs.

The fibre gap

Insufficient nutrients for our gut bacteria have been linked to a loss of certain beneficial bacterial species in western societies and are likely impacting our immunological and metabolic health. Most westerners consume only half of the amount of dietary fibre recommended by dietary guidelines. Nutritionists refer to this as the “fibre gap,” and it is a problem because dietary fibre is the primary source of nutrition accessible to gut bacteria in humans.

Scientists have long promoted the importance of strategically increasing dietary fibre intake as one path forward in regaining gut microbial biodiversity. Although this advice is far from new, the now proven depletion of the microbiome with a fibre deficient diet adds a new perspective to the western diet that we are currently eating.

Comparative studies between rural communities from Africa and South America and industrialised western communities from Europe and North America have revealed specific adaptations of their microbiomes to their respective lifestyles. These adaptations include higher biodiversity and enrichment of Bacteroidetes and Actinobacteria in rural communities, and an overall reduction in microbial diversity and stability in western populations.

Restoring fibre intake can have immediate effects

Some scientists are concerned that a dramatic shift away from a diet similar to the one under which the human-microbiome symbiosis evolved is a key factor in the rise of non-communicable disorders like obesity. There is also a lot of epidemiological evidence that food products containing dietary fibre can help prevent the development of colon cancer and reduce the incidence of coronary heart disease.

It is clear that people living in non-industrialised societies have an average intake of fibre that is much higher than the low norms of western societies. In an experiment scientists compared the effects of a traditional South-African and a modern American diet.  Twenty South Africans gave up their corn porridge and vegetable stews for burgers and fries. And 20 Pittsburghians sacrificed fast food staples for the low-fat, high-fiber fare that South Africans traditionally eat that contained 55 grams of daily dietary fibre. Surprisingly, the Americans had improved markers for colon cancer already within two weeks, while the South Africans showed the opposite effects.

The good news is the finding that changes in the microbiome are largely reversible within a single generation if the fibre intake is increased. However, there are also bad news. With several generations on a fibre deficient diet a progressive loss of diversity is seen, which is not recoverable. So your children and children’s children will lack some of the beneficial microbial species, indicating that extinctions can occur in only a few generations.

Convinced yet?

Veggies

Eat more fibre-rich food

It is recommended to eat 25-30 grams of dietary fibres a day from a variety of foods rich in both insoluble and soluble fibre.

Foods higher in insoluble fibre include:

  • whole grain breads and cereals
  • the outer skins of fruit and vegetables
  • nuts and seeds
  • raw lentil, kidney beans and chickpeas

Foods higher in soluble fibre include:

  • fruits and vegetables
  • dried beans and lentils
  • oats

To help meet your daily dietary fibre requirements look at the below table from the Dietitians Association of Australia:

Food Fibre content
3/4 cup whole grain breakfast  cereal  4.5g
2 slices wholemeal bread 4.5g
1 apple (with skin) and 1 orange  5.5g
2 cups mixed raw vegetables 10g
1/4 cup legumes eg. baked beans 3g
Total 27.5g

A teaspoon of horseradish

Horseradish

Horseradish another superfood if you believe there are such foods.

Here we go again, another superfood. This time with cancer fighting properties. And the scientists say that a teaspoon is enough to achieve the beneficial effects. So what’s not to like?

Well, the pungent aroma and the bitter taste of the food in the first place. We are talking about glucosinolates found in a range of cruciferous vegetables, but in horseradish in particular.

And when the glucosinolates are activated some of the resulting compounds have proven to be protective against cancer. And that we like.

A bit of background

Glucosinolates are natural components of many pungent plants such as mustard, broccoli, cabbage, and yes horseradish. About 132 different glucosinolates are known to occur naturally in plants. As is common, these natural chemicals contribute to a plant’s defence against pests and diseases.

The pungent taste of those plants is due to mustard oils produced from glucosinolates when the plant material is chewed, cut, or otherwise damaged. The plants contain the enzyme myrosinase that is released during chewing and transforms the glucosinolate into mainly isothiocyanate (mustard oil), the active form. The myrosinase and glucosinolates are stored in separate compartments of the plant cells so not to damage the plant itself until chewed.

Glucosinolate type and quantity vary depending on the plant variety, although closely related taxonomic groups typically contain only a small number of the different compounds. Many reviews have addressed the occurrence of some glucosinolates in vegetables with a major focus on negative aspects, like antinutritional or goitrogenic effects. However, there is a positive side now getting increased attention represented by beneficial health properties of some other glucosinolates.

So what are the health benefits?

The metabolic activation of glucosinolates results in the formation of isothiocyanates that in turn have been found to inhibit the development of cancer in several organs in rats and mice, including the bladder, breast, colon, liver, lung, and stomach. Also human epidemiological studies suggest that isothiocyanates are protective against cancers of the lungs and alimentary tract. Studies in animals and experiments with cells grown in the laboratory have identified several potential ways in which these compounds may help prevent cancer by:

  • protecting cells from DNA damage
  • inactivating carcinogens
  • having antiviral and antibacterial effects
  • having anti-inflammatory effects
  • inducing cell death (apoptosis)
  • inhibiting tumor blood vessel formation and tumor metastases.

And now a research team has studied the effects of the glucosinolates present in horseradish. The researchers found different concentrations of allyl isothiocyanate (AITC) and  1-cyano 2,3-epithiopropane (CETP) depending on the horseradish variety. And AITC is the one you want. The team suggests that AITC is a good dietary anti-carcinogen, not only because it activates the enzyme responsible for detoxifying cancer-causing molecules, but also because a large proportion of it, 90%, is absorbed when ingested.

Getting sufficient protection

horseradish-prepared

A teaspoon of horseradish is beneficial to health.

Eating 3–4 portions of broccoli per week has previously been shown to provide a protective effects against certain cancers.

And now the researchers showed that horseradish contains approximately 10 times more glucosinolates than its superfood cousin, broccoli.

So your choice. You can eat 3-4 teaspoons of horseradish a week if you can stomach it, or you can replace each teaspoon by a portion of broccoli if that is more appetising. Or a range of other cruciferous vegetables.

Eating in moderation

Pizza size is all in the eye of the beholder (Photo: Valerio Capello).

Pizza size is all in the eye of the beholder (Photo: Valerio Capello).

In 1978, I visited the USA with two colleagues on a mission to study meat quality. After travelling by car for many hours to reach Texas we got very hungry and stopped at a pizza joint in Oklahoma. We had a choice of small, medium, large and very large pizzas. We settled on one medium each as one should eat in moderation, but huge pizzas each covering half of the table arrived. We couldn’t even eat half of the pizzas.

This highlights that there is no universal measure of eating in moderation.

What is moderation?

Eating in moderation seems to be practical advice for a healthy diet, but a new study suggests that it is an ineffective guide for losing or maintaining weight. The scientists found that the more people liked a food, the more flexible their definitions of moderation were. And who doesn’t like pizza?

Of course moderation is a relative term that doesn’t allow a clear, concise way to guide behaviour as people think of moderation through their own objective lens. They tend to exaggerate what moderation is based on individual perceptions. Frugal Scandinavians might see a five-slice pizza as a satisfying amount, while more generous Americans might desire a ten-slice pizza.

The scientists concluded that people do think of moderation as less than overeating, so it does suggest less consumption. But unfortunately they do think of it as more than what they should eat. So moderation is more forgiving of their desires. The study adds to the growing body of knowledge that suggests people are poor judges of the amounts of food they eat.

In a general backlash against dieting there are now entire healthy eating movements oriented toward the idea of moderation. But those movements assume people can actually be good judges of what they’re eating and what constitutes an appropriate amount, which they obviously are not.

So what to do?

Go for a smaller plate to reduce food intake.

Go for a smaller plate to reduce food intake and still be happy.

A recent Cochrane review of 69 food consumption intervention studies, published between 1978 and 2013, found that people consistently consumed more food and drink when offered larger-sized portions, packages or tableware than when offered smaller-sized versions. This is a little confusing and the researchers stated that the mechanisms underlying the “portion size effect” are not fully understood.

However, people generally perceive the amount served to them as representing an appropriate portion size and consume less when offered smaller portions and more when offered larger portions. The way in which food and drink is presented can also influence consumption. The size and shape of a plate or glass can alter perceptions of quantity and influence how much is consumed.

I repeat, the size of your plate seems to be important in how much you eat. And the size of your glass may influence how much you drink.

In support of this theory another study proved that a larger glass of wine — not the amount in the glass, but the size of the glass itself — might make you drink more. Researchers tracked purchases in a bar over 16 weeks, during which time different sizes of wine glasses were used, small (250 mL), standard (300 mL) or large (370 mL), while the serving of wine was kept at 175 mL. With larger glasses there was an almost 10% increase in wine consumption. It may be that larger glasses change our perceptions of the amount of wine, leading us to drink faster and order more.

Go for smaller tableware

Although it seems natural to eat less with reductions in the portion size presented, it is very interesting to notice the influence of the size of glasses and plates. The solution to overindulgence might be to reduce the size of your tableware. That could be quite helpful and easy to fix at home.

Dark chocolate’s beneficial deeds

Only dark chocolate is beneficial to health (Photo: André Karwath)

There are several different varieties of chocolate (Photo: André Karwath)

Having dealt with hazards in food during a lifetime, it is always nice to be able to look at the benefit side. We all need good news stories. However, even good news stories can be deceptive. There is much fuss made over what is called superfoods, while the overall diet is more important. And scientists test individual food components in isolation reporting highly beneficial effects in unrealistic animal experiments that have no relevance to real life. Resveratrol that can be found in red wine is supposed to be heart protective, but will require daily consumption of many bottles of wine to reach an effective dose.

But dark chocolate seems to be the real thing with normal consumption amounts sufficient to be beneficial to health.

Not all chocolates are the same

Chocolate is made from cocoa solids (cacao), mixed with fat (cocoa butter) and finely powdered sugar to produce a solid confectionery. There are several types of chocolate, dark, milk and white, classified according to the proportion of cocoa solids used in a particular formulation.

Dark chocolate, also known as “bittersweet” or “semisweet” chocolate, contains little or no added sugar, but plenty of antioxidant flavonoids that contribute to the dark colour. More flavonoids means darker chocolate.

Dark chocolate has already been hailed for its positive effects on cardiovascular health and can help lower blood pressure.

Milk chocolate is not a good antioxidant source as milk binds to antioxidants in chocolate making them unavailable.

White chocolate contains no cocoa solids at all and therefore is not a good source of antioxidants.

Let’s look at the details

Nitric oxide reduces blood pressure.

Dark chocolate increases the effect of nitric oxide in reducing blood pressure.

It is widely known that dietary nitrate leads to the substantial elevation of circulating nitrite, which is subsequently converted into bioactive nitric oxide. Bioactive nitric oxide relaxes blood vessels, increases glucose uptake and regulate muscular contraction. Dietary supplementation with nitrate rich beetroot juice has become increasingly popular in athletes and has consistently been shown to reduce oxygen demands during submaximal exercise allowing athletes to go further for longer.

Dark chocolate works a little differently. Cocoa beans contain a substance called epicatechin, a flavanol that releases vasoactive components from the endothelial cells in blood vessels increasing the bioavailability of nitric oxide. The increased bioavailability and activity of nitric oxide dilate blood vessels and increases blood flow, resulting in a reduction of blood pressure. Previous research have shown that as little as 6g per day can reduce mild hypertension, while around 40g per day can increase blood flow also in healthy patients.

Providing an edge

The previous findings have now been confirmed in a study undertaken at London’s Kingston University The scientists found that the tasty treat could help give sports enthusiasts an extra edge in their fitness training. They used a group of nine amateur cyclists. After undergoing initial fitness tests to establish a baseline for comparison, the participants were split into two groups. The first group was asked to replace one of its normal daily snacks with 40g of a dark chocolate for a fortnight, while the other participants substituted 40g of white chocolate for one of their daily snacks as a control.

The effects of the athletes’ daily chocolate consumption were then measured in a series of cycling exercise tests. The cyclists’ heart rates and oxygen consumption levels were measured during moderate exercise and in time trials. After a seven-day interval, the groups then switched chocolate types and the two-week trial and subsequent exercise tests were repeated.

After eating dark chocolate, the riders used less oxygen when cycling at a moderate pace and also covered more distance in a two-minute flat-out time trial.

All good news.

Benefits confirmed by EFSA

Only dark chocolate is beneficial to health (Photo: Simon A. Eugster)

Only dark chocolate is beneficial to health (Photo: Simon A. Eugster)

And the beneficial effects have been confirmed by the European Food Safety Authority.

The Belgian chocolate manufacturer, Barry Callebaut, has exclusive use of an existing authorised claim stating that cocoa flavanols “help maintain the elasticity of blood vessels, which contributes to normal blood flow”. The authorised conditions of use require the product label to state that 200mg of cocoa flavanols are needed for the beneficial effect. The current claim can only be used for cocoa beverages with cocoa powder or for dark chocolate which provides at least a daily intake of 200mg of cocoa flavanols.

There has been concern that authorising claims on products such as chocolate could encourage over-consumption. However, the EFSA Opinion states that the amount required for the effect can be eaten within the context of a balanced diet.

So as long as you keep within your normal calorie intake level, feel no guilt when indulging in some dark chocolate.

Wholegrain or no grain?

BX found in rye grains and other wholegrains.

We have a dilemma. On the one hand science tells us that wholegrains are good for us and particularly for gut health, on the other pseudoscience says that grains were not part of our ancestors diet and should be avoided. Too high amounts of ingested carbohydrates through grains, not just simple sugars so goes the story, are fattening but fat is not. I like my rye bread but happily without butter so what is a simple mind to do?

Enter benzoxazinoids

Well, new scientific findings come to the rescue in the form of benzoxazinoids, or BX for short, found in rye bread and other wholegrain foods. A new name to memorise for a magic natural compound. When it is a matter of health, you can now stick to wholegrain with the BX factor, a group of bioactive health-promoting substances. In Denmark, rye bread is a staple food and most people are aware that rye bread is healthy, but not many know that what makes bread a healthy food is not only vitamins, minerals, protein and fibre but also benzoxazinoids.

Appropriately, the presence of BX in wholegrain was discovered by scientists from Aarhus University in 2010. Certain medicinal plants and young cereal plants have previously been found to contain BX, but it was a revelation that they could also be found in ripened rye and other wholegrains as well as in the final baked bread and other bakery products ready for consumption. Even better, scientists have found that the BX compounds pass through the gut wall and circulate in the body in different chemical forms.

And the benefits

Have a rye-bread sandwich and feel good about it (Photo: Mogens Engelund).

Have a rye-bread sandwich and feel good about it (Photo: Mogens Engelund).

So the scientists wanted to know more. They examined whether BX could have an effect against allergies or whether they regulate the immune system. This part of the study was done by examining blood cells in the laboratory. There was no apparent anti-allergic effect, but there was an effect on the immune system. Eating a diet rich in BX compounds made certain immune system cells react more strongly to some types of bacteria. Previous studies have reported antimicrobial, anticancer, reproductive system stimulatory, central nervous system stimulatory, immunoregulatory, and appetite- and weight-reducing effects of BX or BX derivatives. The health benefits of wholegrain intake may be associated with the solitary or overlapping biological effects of fibers, lignans, phenolic acids, alkylresorcinols, BXs, and other bioactive compounds. All good anyway.

With the new findings in mind, the scientists speculated that it might be possible to grow crops with an optimum content and composition of these health-promoting compounds, so that consumers can increase their BX intake without having to eat large quantities of food.

You can now have a rye-bread sandwich to lunch and feel good about it. Forget about the paleo zealots.

Have you had your sulfoquinovose today?

Why not make your good gut bugs happy?

Make your good gut bugs happy (Photo: Wikimedia).

It’s an honest question but let me rephrase it slightly. Have you eaten your green leafy vegetables today? If this is the case you have probably also been feeding your gut bacteria with sulfoquinovose, or let’s call it SULQ here for simplicity. Nothing to sulk about, it’s a really good thing according to brand new findings. SULQ is hidden in the leaves of green vegetables such as spinach and kale and is devoured by your good gut bacteria, which use it as a source of energy to fuel their growth. And the greener the plant the more SULQ they produce.

Exciting discovery

Researchers have now identified a previously unknown enzyme called YihQ used by bacteria, fungi and other organisms to feed on the unusual but abundant sugar sulfoquinovose. The finding suggests that leafy greens are essential for growing good gut bacteria, and thus denying any space for bad bacteria to colonise the gut. In a critical discovery about how bacteria feed on SULQ, an explanation was found to how the good bacteria protect our gut and promote health. Every time we eat leafy green vegetables we consume significant amounts of SULQ sugars, which are used as an energy source by the good gut bacteria. These beneficial bugs provide a protective barrier that prevents growth and colonisation by bad bacteria.

SULQ has also been shown in other in vitro studies to have anticancer properties, an added benefit.

But there is more

Leafy green vegetables produce megatons of SULQ per year (Photo: Mike).

Green leafy vegetables produce megatons of SULQ per year (Photo: Mike).

As a sulfur-containing sugar, SULQ is produced by photosynthetic organisms like plants at an enormous rate of 10,000,000,000 tons (that is 10 gigaton) per annum and is degraded by bacteria as a source of carbon and sulfur. Sulfur is critical for building proteins, the essential components of all living organisms. SULQ is the only sugar molecule which contains sulfur, and digestion of the molecule by bacteria releases sulfur into the environment, where it re-enters the global sulfur cycle to be reused by other organisms.

This work answers a 50-year mystery that has surrounded how sulfur – an element essential for life on Earth – is used and recycled by living organisms.

If you want to make your intestinal bugs even happier, other foods that also fuel the growth of beneficial bacteria include kefir, artichokes, asparagus, bananas, chicory, dandelion root, garlic, jicama, leeks, onions, barley, rye and wheat. Your choice.

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The intricate effects of coffee on human health

The details of what we eat is not easy to capture (Photo: Christina Roervik)

The details of what we eat is not easy to capture (Photo: Christina Roervik).

I know, most often on this blog we don’t put much value on epidemiological studies linking disease over decades to food consumption captured by a one-time limited food frequency questionnaire at the beginning of the study period. Knowing the limited reliability of such a food consumption method, intricate relationships between different food groups and changes in food consumption patterns with increasing age it is surprising that it is even called science. But this time it might be different (or is that wishful thinking from our side?).

A new study praises the benefits of coffee

This new epidemiological study of coffee consumption and health is quite elaborate. Firstly, it involved 208,501 participants with 31,956 deaths in three large cohort studies allowing detailed statistical calculations. Secondly, it repeated the food frequency questionnaire each four years to capture food pattern changes. And thirdly, it actually validated the food frequency questionnaire against a multiple week dietary record showing a correlation of 0.74 and reproducibility of 0.80. So a good starting point strengthened by the fact that previous studies have shown that coffee intake is one of the food items showing the highest validity and reproducibility when using food frequency questionnaires and a beverage less prone to misreporting.

Detailed information on caffeinated and non-caffeinated coffee consumption was available as well as other dietary and lifestyle factors. The initial analyses showed a positive correlation between coffee consumption and smoking and because of the deleterious effects of smoking on health, smokers were excluded from the further analyses.

In summary, the good news showed that regular consumption of coffee was inversely associated with risk of total mortality and in particular mortality due to cardiovascular disease and neurological diseases like Parkinson’s. No significant association between coffee consumption and total cancer mortality was found, so unless the International Agency for Cancer Research (IARC) has 799 studies showing the opposite, coffee should be in the clear (I am referring to the dubious nomination by IARC of whole categories of meat or meat products as cancer suspects based on 800 studies we have not yet been able to verify).

Optimal coffee consumption

Three to five daily cups of coffee optimal for health.

Three to five daily cups of coffee optimal for health.

Three to five cups a day seemed to have the optimal protective health effects with the mortality rate 12% less compared to non-coffee drinkers. Similar associations of caffeinated and decaffeinated coffee consumption with risk of total and cause-specific mortality were found. Thus the caffeine is not the protective compound. There are several other compounds in coffee that could be responsible for the positive effects. The authors list chlorogenic acid, quinides, lignans, trigonelline and magnesium as likely contenders as they reduce insulin resistance and systemic inflammation that in turn might prevent diabetes as well as cardiovascular disease.

There could be another reason linked to the dubious findings of IARC and meat consumption. Apart from the obvious culprits associated with meat consumption, like polycyclic aromatic hydrocarbons formed during wood smoking and barbecuing, nitrite added to processed meats and heterocyclic amines formed during high temperature frying, the only compound inherent to meat itself (providing some justification for nominating a whole food category as carcinogenic) is haeme iron. As it happens haeme iron is an excellent source of bioavailable iron, but new research points to excess iron being responsible for a range of human illnesses as well as promoting bacterial growth (in a further blog we will delve into the details of the influence of iron on human health).

Why not try a cup of coffee after dinner?

Now a cup of coffee after dinner inhibits the efficient uptake of iron by the human body. This might be a double whammy in that you can enjoy your red and processed meat without much worry and get an extra kick by the coffee. We told you about the importance of the whole diet with intricate relationships between different food groups.

Maybe IARC should be a bit more careful in the future in looking at individual foods, otherwise it will not be much left to eat. Arsenic in rice cause cancer, too much milk has been associated with prostate and breast cancer, a range of refined and processed foods contribute to weight gain with obesity a factor in cancer development. The list goes on and on. But stick to coffee and you might be fine (although your sleep pattern might be disturbed by a late cup).

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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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