How much coffee in your coffee?

A cup of coffee to raise the spirit.

A cup of coffee to raise the spirit.

A bit cryptic I agree and the question should rather be how much caffeine do you think you have in your cup of coffee? But since you have no way of measuring that, unless you have access to a chemical laboratory, you can only control the amount of coffee beans you use for your cup of coffee and the brewing method. And you can use those measures as a proxy for the amount of caffeine you consume.

Why worry about the amount of caffeine?

Because the European Food Safety Authority (EFSA) has just published an opinion on caffeine and alertness. This new opinion confirmed that at least 75 mg of caffeine is necessary to improve alertness. For some reason SmithKline Beecham Limited wished EFSA to agree that 40 mg of caffeine would have the same effect. But EFSA didn’t budge. EFSA was clear in saying that

at the particular dose range between 40 and < 75 mg, no effect of caffeine was found on the majority of outcome measures of reaction time

after reviewing a number of studies submitted by the applicant.

The EFSA scientists also believed that

“increased alertness might be a beneficial physiological effect”

and I assume we all take that for a given. So there you have it, your cup of coffee needs to contain at least 75 mg of caffeine to wake you up.

How to get enough caffeine in your cup of coffee?

As a rule of thumb it’s usually presumed that a regular cup of coffee contains 100 mg of caffeine but it may range between 40 and 176 mg and to be honest the mean is probably closer to 80 mg. This will fit with the standard recipe when calculating exposure of 7 g of ground coffee beans for a cup, which would result in close to 80 mg of caffeine in the cup since arabica coffee beans contain about 11 mg/g. So far so good and we would be over the magical 75 mg caffeine alertness level.

But remember that we haven’t yet looked at the volume of coffee in the cup. The size of a cup can vary from as little as 25 mL (Greek coffee) to a large cup of 330 mL and in extreme cases up to 480 mL for a Starbucks Pike Place cup or a McDonald’s Mocha Frappe. The volume of coffee in an average cup in Europe is actually 120 mL, while in the USA it would be closer to 240 mL.

Large variations in the size of a cup of coffee (Photo: akatori)

Large variations in the size of a cup of coffee (Photo: akatori)

So how does the volume of coffee influence the caffeine level? As it happens not that much since we seem to keep the caffeine level fairly constant for a cup irrespective of size. An Italian espresso of 30 mL would still contain a minimum of 40 mg of caffeine and could be close to the 75 mg mark. This is strong coffee but might be a little low in caffeine to reach the EFSA benchmark. On the other end of the spectrum is a typical 240 mL American cup of coffee that might not hold more than 95 mg of caffeine. Not so strong I would say, no offence intended, but well over the desired level if you drink it all. Even the large McDonald’s Mocha Frappe of 480 mL limits the caffeine to 125 mg per cup, but Starbucks Pike Place is not so restrictive offering 330 mg of caffeine per 480 mL cup.

Confused again?

Well I have to confuse you even more because tastes are different and brewing methods abound. If you go for robusta coffee and use the same amount of beans as for arabica you would double your caffeine intake.

You might think that a strong, rich flavour would indicate an extra dose of caffeine, but the truth is that light roasts actually pack more of a jolt than dark roasts. The process of roasting burns off some caffeine.

And finally, while the caffeine concentration in a normal brew of filtered coffee would amount to 0.6-0.8 mg/mL, it would be 1.7-2.3 mg/mL in the coffee expressed from an espresso coffee machine. But you would obviously pick the size of your coffee cup accordingly to not overindulge.

All I can say is that if you feel alert you have probably exceed the 75 mg of caffeine required to improve your reaction times. Good on you, you will get through the day at your peak.

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Is sugar a public health enemy?

Popular low-fat products (Photo: Barry Ennor)

Popular low-fat products (Photo: Barry Ennor)

You have probably picked low-fat food products over full-fat products for quite some time since high fat consumption was claimed to be linked to heart disease. And now it’s time to cut back on your sugar consumption as well. What pleasures are left in life? Problem is that sugar consumption is on the increase. By the start of the 1970s, supermarket shelves were full of low-fat yogurts, spreads, and even desserts and biscuits. When creating their low-fat products, manufacturers needed a fat substitute to stop the food tasting like cardboard, and they picked sugar.

However, it has long been questioned whether a diet high in sugars, especially refined sugars, is bad for human health. In 1972, John Yudkin, founder of the nutrition department at the University of London’s Queen Elizabeth College, published a book called “Pure, White and Deadly” where he questioned the link between fat and heart disease and instead put the blame on sugar. After all, he wrote, we had been eating substances like butter for centuries, while sugar, had, up until the 1850s, been something of a rare treat for most people. This was not what the low-fat proponents wanted to hear and as a result there was a concerted campaign mounted to discredit the work of Yudkin.

More evidence that excessive sugar intake is bad for health

Now there is a mounting pile of evidence suggesting that Yudkin was right and that excessive sugar intake is worse for the body than we ever suspected. Many studies have linked high sugar consumption to obesity, and a possible contributor to diabetes, cardiovascular disease, dementia, macular degeneration and tooth decay. Mind you, these are observational studies, which can prove association but not cause and effect.

Still it might pay off to heed the advice. It is clear that most of us should cut back on the sweet stuff. The World Health Organization (WHO) recommends that less than 10% of our energy should come from free sugars. Free sugars are defined by the WHO as all sugars “added to foods by the manufacturer, cook, or consumer, plus sugars naturally present in honey, syrups and fruit juices”. That is a stretch target for most of us. And if that is not enough, now there are rumours in the press that this target might be reduced to 5%, which is equivalent to five teaspoons or 20 g. This is not going to be easy.

Let’s look at some facts. The world produced about 168 million tonnes of sugar in 2011. The United Nation’s Food and Agriculture Organization estimates that average global added sugar consumption is about 24 kg a year – equivalent to 65 g or about 260 kcal a day. Of course this is not evenly spread around the world. Consumers in the United States of America is at the top of the per capita total consumption of sugar (including high-fructose corn syrup used in only a handful of countries) with about 64 kg per year, while China is close to the bottom with about 6 kg per year. I have borrowed a graph from the blog of the Conversable Economist to illustrate the spread in energy intake from sugar in different countries. The orange bit is the high-fructose corn syrup.

Calory sweetener

But how do you reduce sugar intake

It is useful to know that a single can of cola contains ten teaspoons of sugar, a Mars bar has five, a bowl of Coco Pops has about four and there are eight in some ready meals. If the ingredient list for a food includes words like sucrose, glucose, fructose, high-fructose corn syrup, honey, agave syrup, fruit juice concentrates, invert sugar, cane sweetener, maltose, malt syrup, dextrose and dehydrated cane juice, you will know that part or all of the sugars listed on the nutrition label come from added sugars. That’s when it is time to react.

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Energy burning brown fat

The painful way of forming brown fat (Photo: Pavel Trebukov)

The painful way of forming brown fat (Photo: Pavel Trebukov)

You’re out there freezing (assuming you live in the Northern Hemisphere, here in Australia it’s summer). You’re shivering and actually feel some warmth. It is your muscles burning off energy to warm you up a little bit. But what you don’t know is that at the same time the muscles release irisin. The irisin goes straight to your white fat cells and some are gradually transformed into brown fat cells and activated. And the brown fat cells burn energy rather than storing it relieving the muscles from some shivering activity. Clever don’t you think?

Some puzzling findings

But let’s take a step back. Babies are actually born with a supply of brown fat in the neck region. This is nature’s way of helping infants to keep warm by burning energy when needed. When growing up the brown fat disappears. Or so it was thought. But brown fat has been rediscovered in adulthood in the same neck region. Now a new study suggests that shivering and moderate exercise are equally capable of stimulating the conversion of energy-storing white fat into energy-burning brown fat. Around 50 g of white fat stores more than 300 kilocalories of energy. The same amount of brown fat could burn up to 300 kilocalories a day. Quite a difference. There are a few puzzling findings here. It makes sense for shivering to produce and activate brown fat to help in the process of keeping warm. But the communication between muscle and fat through the irisin hormone to achieve this is quite astonishing. Even more surprising is the fact that exercise can achieve the same result. It is not intuitive since exercise produces heat. It is speculated that muscle contractions during exercising mimic shivering and thus achieve a similar effect. The scientists found that around 10-15 minutes of shivering resulted in equivalent rises in irisin as an hour of moderate exercise. Just be aware that it might take up to a week for the brown fat to be fully developed.

The facts about brown fat

The less painful way of forming brown fat (Photo: Steve Garner)

The less painful way of forming brown fat (Photo: Steve Garner)

We now know that brown fat is present in most, if not all, adults. Adults with more brown fat are slimmer than those without. When we are cold, we first activate our brown fat because it burns energy and releases heat to protect us. When that energy is insufficient, muscle contracts to produce shivering, thereby generating further heat. The brown fat can provide around 20% of the heat needed, representing a proportion of total energy expenditure sufficient to impact the body’s long-term energy balance. There is excitement in the brown fat field because its energy-burning capacity makes it a potential target to combat obesity. Glucose levels are also lower in humans with more brown fat, potentially providing protection against diabetes.

Your daily treat

So there you have the food connection. As long as you regularly exercise for about an hour or, if you prefer, spend 10-15 minutes in a cold room at 12-14˚C you can have your daily ice cream without putting on weight. I know what I prefer to do.

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Low-fat yoghurt anyone?

Low-fat yoghurt good for health claim researchers

Low-fat yoghurt good for health claim researchers

I’m a fan of low-fat Greek yoghurt so of course I had to take note when British researchers claim that eating 80 g/day can prevent the development of type 2 diabetes. They had selected 4,255 men and women for the study from a larger cohort of 25,000 involved in the EPIC-Norfolk study. This included 753 people who developed type 2 diabetes over 11 years of follow-up and 3,502 randomly selected people for comparison.

But hang on there, isn’t EPIC the European Prospective Investigation into Cancer and Nutrition? One of the type of epidemiological studies that I am very suspect of in relation to diet correlations. Well, yes but maybe this time they could be right.

Actually, they had abandoned the typical food frequency questionnaire (FFQ) that is commonly used to record food consumption and replaced it with a prospective 7-day food consumption diary. I think the FFQ is a joke and should not be used for serious food studies. Of course the diary method is a big step forward. Still it was used only once to capture food consumption during a single week and 11 years later they tried to link this ancient food pattern with the development of type 2 diabetes. A little suspect!

So what did they find?

According to the results, eating a normal portion of yoghurt could reduce the risk of developing diabetes by 28%, compared to eating very little or no yoghurt at all. Expanding that to any low-fat fermented dairy product, such as low-fat cheese, still cut the risk by 24%.

In public-health terms this would involve consuming 4.5 standard-size portions (125 g) per week of low-fat fermented dairy products, mainly yoghurt and unripened cheese such as cottage cheese and fromage frais.

The researchers also looked at diets containing cake, pudding, biscuits, or chips and concluded that eating yoghurt instead of such snacks resulted in a 47% lower risk for diabetes. No other food substitution resulted in a significant reduction in diabetes risk.

To be plausible there has to be a reasonable mechanism that can explain the results. In this case it could be due to promotion of the synthesis of menaquinone (vitamin K2), which has been linked to reduced rates of type 2 diabetes, or the actions of probiotic bacteria, which have been found to improve lipid profiles and antioxidant status in patients with type 2 diabetes.

Read the nutrient information panel

Be careful with the sugar content (Photo: Judy van der Velder)

Be careful with the sugar content (Photo: Judy van der Velder)

Before you jump on the low-fat-yoghurt bandwagon just a few reflections. The first relates to the cut-off level for fat used by the researchers. They considered products with less than 3.9% fat as low-fat. In Australia, full-fat yoghurt commonly contains 3.4% fat except for Greek and European style yoghurt. Also, if you read the ingredient list for low-fat yoghurt you will find that the fat is commonly replaced with sugar and the actual energy level might even be increased. So be a bit careful in the brand of yoghurt you go for.

But who am I to spoil the fun. The researchers were pleased to note that while other research looked at certain foods that raise health risks, such as consuming high amounts of added sugar, they were happy to report on foods, like yoghurt and low-fat fermented dairy products, that could be good for our health.

A good news story among all the doom and gloom.

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You should try black rice

Rice is the most important grain crop in the world (Photo: Claudia Gold)

Rice is the most important grain crop in the world (Photo: Claudia Gold)

Did you know that rice is the most important grain in the world providing more than one fifth of the calories consumed by humans? It is a staple food in most Asian countries with annual per capita consumption of around 80-90 kg. Indonesia tops the consumption table with an annual per capita consumption of close to 160 kg. Rice consumption in Western countries is a trickle compared to the Asian volumes with annual per capita consumption of about 14 kg in the USA and Australia and only 6 kg in Europe as a whole.

White or brown?

White or so called polished rice is the most commonly consumed in Asian countries. It is rice which had its hull, bran and germ removed. Since the bran contains a small amount of oil that can turn rancid, rice is polished to prolong its shelf-life but this process also removes some essential nutrients. Brown rice has a higher nutritive value by retaining the bran and germ. It was long a popular choice in Japan, but the trend has been changing with white rice more in favour lately. This is seen as being influenced by a Westernised diet.

It is a peculiar anomaly then that the trend is the opposite in Western countries. Brown rice has been gaining market share in the USA where sales doubled over a five-year period. A similar trend has been observed in parts of Europe because it is seen as a healthier choice over ordinary white rice. In 2008, the U.S. Food and Drug Administration extended the whole grain health claim to brown rice, stating that diets rich in plant foods and whole grains like brown rice, and low in total fat, saturated fat and cholesterol, may help reduce the risk of heart disease and certain types of cancer.

Subaleurone layer important to health

Now a plausible explanation has been found for the added benefits of brown rice. First it is important to know that when brown rice is polished to make white rice, what is called the subaleurone layer located between the white center of the grain and the brown fibrous outer layer is stripped away. In a collaborative effort, researchers at Temple University School of Medicine in Philadelphia and the Nagaoka National College of Technology in Japan were able to show that components in the subaleurone layer inhibited angiotensin II activity. Angiotensin II is a peptide hormone and a known culprit in the development of high blood pressure and atherosclerosis. So far so good.

To add further benefits to brown rice, researchers at the Jiangnan University in China found that germination of the rice can be used to improve its taste and further enhance its nutritional value and health functions. Germinated brown rice is richer in vitamins, minerals, dietary fibers, and essential amino acids, and contains more bioactive components, such as ferulic acid, γ-oryzanol, and gamma aminobutyric acid. Germinated brown rice has been reported to exhibit physiological effects associated with reductions in the risk of some chronic diseases.

Bewildering choice of rice varieties

Black rice a good nutritional choice (Photo: Joan Nova)

Black rice a good nutritional choice (Photo: Joan Nova)

But it doesn’t stop there. There is a bewildering choice of unpolished rice varieties classified according to their colour. “Brown” is actually a collective description of unpolished rice that can have many colours so don’t be confused. Brown rice, that actually is brown in colour, contains almost five times the fibre and twice the iron of white rice. Then we have red rice that contains a similar amount of fibre to brown rice but twice the amount of iron and six times the amount of zinc. A variety of anthocyanins give its bran a red/maroon colour. Black rice contains about three times the amount of fibre compared to brown rice. It has a different combination of anthocyanins colouring the bran layer black and turning deep purple when cooked. Purple rice is a short grain variant of black rice known as “Forbidden Rice,” since in ancient China it was reserved for the emperor and nobles, and commoners were prohibited from eating it. It is purple in its uncooked state and deep purple when cooked. It contains similar amount of fibre but almost twice the iron and four times the zinc content of brown rice.

Fibre is beneficial to health as we all know and iron and zinc are necessary trace elements. But what about anthocyanins? Anthocyanins are responsible for the red, purple, and blue colors of many fruits, vegetables, cereal grains, and flowers. They belong to a class of molecules called flavonoids with powerful antioxidant properties in the test tube. According to research from the Department of Food Science at Louisiana State University, a spoonful of black rice bran contains more anthocyanin antioxidants than a spoonful of blueberries, but with less sugar and more fibre and vitamin E antioxidants. So life should be good.

The impact of anthocyanins?

But here is the spoiler. Although a powerful antioxidant with an ability to scavenge free radicals three to five times better than vitamins C or E in the test tube, anthocyanins have little or no value in that role in the human body. How is that? Well, usually less than five per cent of the anthocyanins are absorbed by the body, and most of what does get absorbed into the blood stream is rapidly metabolised and excreted. By contrast, vitamin C is absorbed 100 per cent by the body and accumulates in cells where it is 1,000 to 3,000 times more active as an antioxidant than anthocyanins.

However, don’t despair, clever scientists have found another mechanism with which anthocyanins benefit health. They appear to strongly influence cell signaling pathways and gene expression important in preventing cancer. They 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 effects could be long-lasting compared to antioxidants, which require constant replenishment through diet. A healthy diet with five servings of fruit, vegetables and why not some black rice would provide a sufficient amount of anthocyanins to trigger the beneficial effects. Large doses taken via dietary supplements might do no additional good or even cause harm.

The balance of good and bad (Photo: The op life)

The balance of good and bad (Photo: The op life)

Good or bad?

There is one remaining caution necessary and that is the higher concentrations of heavy metals found in unpolished rice. Arsenic can be a concern. Scientists from the US Food and Drug Administration have been locking at inorganic arsenic levels in rice. Although they concluded that levels of the chemical were low and didn’t pose short-term health risks, they found higher levels in less processed rice like brown rice.

Australian scientist have just published results from an investigation of concentrations of a range of heavy metals in Australian grown and imported rice. The concentrations varied extensively depending on their country of origin and variety. Unfortunately, brown rice contained the highest heavy metal concentrations pointing to rice bran as a significant source of the total heavy metal burden in rice grain.

As usual there is a critical balance between good and evil (or as the current Prime Minister of Australia would say: goodies and baddies). In this case I believe that a black rice meal now and then will do mainly good.

Food is in while supplement pills are out

Skewed diet and no pills (Photo: Tony Evans)

Skewed diet and no supplements go together (Photo: Tony Evans)

This blog is not for you if your main meals consist of McDonald’s burgers and KFC chickens, you only drink soft drinks and Red Bull, and you eat doughnuts instead of wholegrain bread, because you would never even contemplate to take vitamin or mineral supplements. You might need it though.

But if you eat a varied diet and worry about your nutrition, it is very likely that you would also supplement your diet with multivitamins and minerals. This is a real conundrum because if you are in the latter group you actually satisfy your vitamin and mineral needs through your diet and don’t need the supplements.

And did you know that the supplements can actually do more harm than good? I guess you didn’t. It is all about p53, but more about that later.

Too much of a good thing

Don’t get me wrong, vitamins and minerals are absolutely necessary for the body to maintain good health. This has been known for a reasonably long time, with possibly the best example being the complete cure of scurvy with vitamin C. Scurvy was a terrible disease that plagued humans long back through recorded history, but now a rarely seen condition. Many other vitamins and micronutrients are required for good health.

Antioxidants, like selenium, and the vitamins A, C and E, fight free radicals that can damage DNA, cell membranes, and the lining of arteries. Deficiencies can cause all sorts of diseases, some of them very serious. Several studies have shown that people who eat more fruits and vegetables that contain plenty of antioxidants have a lower incidence of cancer and heart disease and live longer. The logic is obvious that if people who eat lots of fruits and vegetables are healthier, then people who take supplemental antioxidants should also be healthier.

But not so. Remarkably, studies involving tens of thousands of subjects have shown that high doses of vitamins and supplements, rather than being helpful, lack beneficial effects or can sometimes even be harmful to health. It seem that humans are adapted to getting nutrients from whole foods and not through pills. Most nutrients require enzymes, synergistic co-factors and organic mineral-activators to be properly absorbed. While these are naturally present in foods, they are often not included in synthetic vitamins with isolated nutrients.

And I have the science to prove it.

Vitamins

Vitamin and mineral supplements can even be harmful (Photo: Steven Depolo)

An evaluation of 38,772 older women found that several commonly used dietary vitamin and mineral supplements, including multivitamins, vitamins B6, and folic acid, as well as minerals like iron, magnesium, zinc, and copper, were associated with a higher risk of total mortality. Iron was of particular concern since it was strongly and dose dependently associated with increased total mortality risk.

A study of 35,533 men found that the risk of prostate cancer increased for the men taking vitamin E, selenium, or both. Although the increased risk was small, it was clear that neither of these supplements was helpful against prostate cancer.

In reviewing 27 trials looking at the efficacy of vitamin supplements in 400,000 adults with no nutritional deficiencies, the typical supplement customers, no clear evidence of a beneficial effect of supplements on all-cause mortality, cardiovascular disease, or cancer could be found.

Daily multivitamins to prevent cognitive decline among 5,947 elderly men didn’t improve overall cognitive performance or verbal memory. After 12 years of follow-up, there were no differences between the multivitamin and placebo groups.

Many more trials have assessed the role of vitamin and mineral supplements in primary or secondary prevention of chronic disease and have consistently found no beneficial effects or even possible harm. Beta-carotene, vitamin E, and possibly high doses of vitamin A supplements have been seen to increase mortality. How is that?

It might be the p53

The p53 is a gene that has been dubbed the guardian of the genome, your DNA. Its job is to detect and destroy cells with defective DNA, including early cancer cells. Of course you don’t want to interfere in that process, but you might inadvertently do just that by taking extra antioxidants. A team of Swedish scientists has now proved that antioxidants can fuel growth of lung cancers. Antioxidants are supposed to protect healthy cells from chemically unstable oxygen molecules that can damage DNA and cause cancer. But they also shut off the p53 gene, thus allowing cancer cells to grow and divide faster than usual.

So the research results presented above that seemed a bit suspicious at first now has a plausible explanation. Basically, antioxidants help early tumours to survive and grow and can thus increase mortality. The opposite to what you want.

Stop the pill popping

Fruit (Photo: Mariia Kravtsova)

A balanced diet with plenty of fruit and vegetables is sufficient for most people (Photo: Mariia Kravtsova)

The simple truth for the general population with no clear evidence of micronutrient deficiencies is that most supplements do not prevent chronic disease or death. Their use is not justified, and they should be avoided since some might even be harmful. Supplements are only needed where there is a demonstrable micronutrient deficiency. The most promising data in the area of nutrition and positive health outcomes relate to dietary patterns, not nutrient supplements. In most cases, eating lots of fruit and vegetables, and a balanced diet, will provide all micronutrients and vitamins needed. So maybe you should skip that burger tomorrow and go for an apple.

References