Go easy on the toast

We are quick to blame the food industry for all that is wrong with the food supply. Plastic residues in baby food, process contaminants in soy sauce, too much fat in the burgers, too much salt in the soup. I could go on and on and rightly so but did you know that there are some easy steps you can take as well to reduce contaminant formation? Today’s blog will focus on the simple toast. Even the most challenged cook can prepare toasted bread, but do we all know what dangers can lurk in there?

Be the master of the toaster (Photo: Donovan Govan)

Be the master of the toaster (Photo: Donovan Govan)

To state the obvious, toast is bread that has been browned by exposure to radiant heat. This browning is the result of Maillard reactions that alter the flavour of the bread. Bread has been toasted for centuries, initially to make stale bread more palatable. Open flame toasting or oven toasting have now been mostly replaced by the custom made toaster with a more precise control of the degree of toasting. And it is here you come in because you can steer the degree of browning by controlling time and temperature and thus the amount of Maillard reaction products that are formed.

The browning reaction

Just a few words about the Maillard reaction so you get the importance of the events happening during heating. It is actually vitally important in the preparation or presentation of many types of food and is named after chemist Louis-Camille Maillard, who first described it in 1912. It is a form of nonenzymatic browning involving a chemical reaction between amino acids and reducing sugars in the food, usually but not exclusively requiring heat. In the process, a complex mixture of hundreds of different flavour compounds are created. These compounds, in turn, break down to form yet more new flavour compounds, and so on. Most of these new molecules are produced in incredibly minute quantities, but that doesn’t mean they’re unimportant. Each type of food has a very distinctive set of flavour compounds that are formed during the Maillard reaction.

There are two factors, dryness and temperature, that are the key controls for the rate of the Maillard reaction. High-temperature heating speeds up the Maillard reaction because heat both increases the rate of chemical reactions and accelerates the evaporation of water. As the food dries, the concentration of reactant compounds increases and the temperature climbs more rapidly.

Acrylamide formed during toasting

Unfortunately, acrylamide is one Maillard reaction product formed at high temperatures. Production of acrylamide during heating is temperature-dependent and increases as food is heated for longer periods of time.  Its discovery in some cooked starchy foods in 2002 prompted concerns about the carcinogenicity of those foods. In laboratory studies, acrylamide had been shown to cause cancer in animals, but at levels much higher than those seen in foods. Experiments are still underway to determine whether the much lower levels of acrylamide seen in food pose a health risk to people.

Toast bread to light brown and avoid burning it (Photo: DaGoaty)

Toast bread to light brown and avoid burning it (Photo: DaGoaty)

In the meantime it may pay off to be cautious. Certain foods are more likely to contain acrylamide than others. These include potato products (especially French fries and potato chips), coffee, and foods made from grains (such as breakfast cereal, cookies, and toast). These foods are often part of a regular diet. But if you want to lower acrylamide intake, reducing your intake of these foods is one way to do so.

Toasting bread to a light brown color, rather than a dark brown color, lowers the amount of acrylamide. Very brown or black areas contain the most acrylamide. So go easy on the toaster to be on the safe side.

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Madness in blaming acidogenic food

Here we go again, you do think that some myths proven wrong would disappear. But not so. This time it is a dubious epidemiological study (yes I know I have a bias against spurious epidemiological results) that is claiming a relationship between acidifying foods and diabetes without a believable mechanistic theory to explain the results.

Let’s start from the beginning to better understand why the researchers even thought about testing the influence of so called acid producing foods on the development of type 2 diabetes.

Body regulation of pH

The pH of different items (Illustration: Edward Stevens)

The pH of different items (Illustration: Edward Stevens)

In the early 20th century nutritionists coined the term acidic and alkaline diets describing a group of foods that was supposed to be able to affect the pH of bodily fluids like blood and urine. As I am sure you know acidity-alkalinity is expressed on a pH scale with 7 as neutral between the two. A pH of 0 is completely acidic, and a pH of 14 completely alkaline. Blood happens to be slightly alkaline, with pH maintained in a very close range of between 7.35 and 7.45. The theory of the alkaline diet proposed that eating certain foods would help maintain the body’s ideal pH balance to improve overall health. But we now know that the body maintains its pH balance regardless of diet. This is very important and thus precise regulatory mechanisms make sure there are no deviations.

But pH is not constant across the body. On the contrary, the stomach has a pH ranging from 1.35-3.5. It must be acidic to aid in digestion. Urine can also be acidic and this is the one area in which the diet may affect the pH level. The role of the diet and its influence on the acidity of urine has been studied for decades. Urine excretion is actually a clever way of balancing our overall body pH.

Diet will not influence blood pH

Next we should look at the purported acidic and alkaline diets. And this is not as easy as it sounds. You would think that the acid in foods like lemons, grapefruit and even tomatoes would cause the trouble, but this is not the case. Instead, it is claimed that meat, fish, poultry, dairy products, processed foods, white sugar, white flour, alcohol and caffeine produce acid in the body after they’ve been digested. On the contrary, the alkaline diet is mostly vegetarian. In addition to fresh vegetables and some fresh fruits, alkaline-promoting foods include soy products and some nuts, grains, and legumes.

There’s no doubt that replacing sausages and potato chips with fruits and vegetables is good for you. But this has nothing to do with the alkalinity of the diet, rather basic facts about nutrition and physiology. No matter what we eat, the pH of our blood is going to stay the same.

The term “alkaline diet” has been used by alternative medicine practitioners, with the proposal that such diets treat or prevent cancer, heart disease, low energy levels as well as other illnesses. These claims are not supported by medical evidence and make assumptions about how alkaline diets function, contrary to current understandings of human physiology. The “acid diet” has also been considered a risk factor for osteoporosis, though more recently, the available weight of scientific evidence does not support this hypothesis.

The new epidemiological results

Diet and diabetes studied in 10,000 women (Photo: The Advocacy Project)

Diet and diabetes studied in 60,000 women (Photo: The Advocacy Project)

Now researchers propose that an acidic diet may be associated with up to a 56% increased risk of type 2 diabetes. They followed more than 60,000 women over 14 years in order to assess whether dietary acid load impacted later risk of type 2 diabetes. At the beginning of the study the women had to complete a food frequency questionnaire. From the collected dietary data they calculated a potential renal acid load at that time and then followed the women for 14 years recording new cases of diabetes. Assuming that their diets stayed the same over that long time span, they concluded that dietary acid load 14 years ago was linked to increases in the incidence of type 2 diabetes.

While there have been recent improvements in recognising different variables that can affect acid excretion in urine, the level of detail needed to predict the urinary pH based on diet is still daunting. Precise calculations require very detailed knowledge of the nutritional components of every meal as well as the rate of absorption of nutrients, which can vary substantially from individual to individual, making effective estimation of potential renal acid load very difficult.

Although the research team attempted to adjust for confounding factors, there could be many other reasons for their findings. Intake of various macronutrients and food categories were very different across the diet groupings. The high acid group consumed the least magnesium and magnesium has previously been inversely linked to type 2 diabetes. The high acid group consumed the fewest vegetables. Although the evidence is somewhat unclear, vegetable intake is usually associated with a reduced risk of type 2 diabetes, particularly root vegetables and leafy greens. Coffee is one of those consumables that everyone knows is bad for you but which is actually linked to a number of health benefits, including a reduced risk of type 2 diabetes. The high acid group consumed the least coffee. We could go on and on.

The myth exposed

That diets high in acid producing elements will lead the body in general to become acidic and foster disease goes against “everything we know about the chemistry of the human body” and has been called a “myth” in a statement by the American Institute for Cancer Research. Unlike the pH level in the urine, a selectively alkaline diet has not been shown to cause a sustained change in blood pH levels, nor to provide the clinical benefits claimed by its proponents. Because of the body’s natural regulatory mechanisms, which do not require a special diet to work, eating an alkaline diet can, at most, change the blood pH minimally and transiently.

What you eat can have a profound affect on your health, but the acidity or alkalinity of foods is not important. As has been stated in another blog, eat your vegetables and fruits. Get your micronutrients and plant polyphenols. Drink your coffee. Try not to eat so much food that you gain weight and overload your cells’ ability to handle the energy. Exercise consistently and intelligently. And you will be fine without worrying about acid producing food.

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Do you trust herbal supplements?

Cart in Mexico selling herbal remedies (Photo: Wikimedia)

Cart in Mexico selling herbal remedies (Photo: Wikimedia)

Herbal supplements, sometimes called botanicals, aren’t new. As a matter of fact, the use of medicinal plants is the most common form of traditional medication worldwide. They have been used by human medicine for thousands of years. A considerable part of commercial pharmaceuticals currently on the market are derived from botanical sources. Examples include aspirin (from willow bark), quinine (from the quinine tree) and digoxin (from the foxglove plant). But pharmaceuticals have gone through extensive testing, herbal supplements have not.

The international trade in herbal supplements is a considerable part of the global economy and the demand is increasing in both developing and developed nations. There are currently more than 1,000 companies producing medicinal plant products with annual revenues in excess of US$60 billion. Echinacea to prevent colds. Ginkgo to improve memory. St. John’s wort to treat mild depression. Flaxseed to lower cholesterol. The list of herbal remedies goes on and on. There are now a bewildering 29,000 different products available on the market.

New research uncovered fraud

There is nothing inherently wrong in trusting herbal remedies, as long as you know what you’re getting. And do you? Maybe not according to new research.

Using a test called DNA barcoding, a kind of genetic fingerprinting that has also been used to help uncover labelling fraud in the commercial seafood industry, Canadian researchers tested 44 bottles of popular supplements sold by 12 companies. They found that pills labelled as popular herbs were often diluted — or replaced entirely — by cheap fillers like soybean, wheat and weeds. A bottle labelled as St. John’s wort was made of nothing but rice. They also found that many supplements were not what they claimed to be. For instance, the study found that one product advertised as the North American black cohosh, a popular remedy for hot flashes and other menopause symptoms, actually contained the related Asian baneberry plant that can be toxic to humans.

Some herbal supplements were discovered to be adulterated with ingredients not listed on the label. Such contamination could pose serious health risks to consumers. For example, they identified black walnut contamination in a gingko product and contamination of many products with Santa Maria feverfew. This latter plant can trigger respiratory and skin reactions in people. One of the bottles tested even contained Alexandrian senna, a powerful laxative made from an Egyptian yellow shrub.

Product substitution occurred in 30 of 44 of the products tested and only two of the 12 companies had products without any substitution, contamination or fillers. Many people assume that if their local pharmacy or health food store carries a particular herbal supplement, it can’t be harmful. But it certainly can since many contaminants will have significant medical effects.

How serious is it?

Not necessarily safe because it is sold in a pharmacy (Photo: Chris de Rham)

Not necessarily safe because it is sold in a pharmacy (Photo: Chris de Rham)

Some of the adulteration problems may be inadvertent. Cross-contamination can occur in fields where different plants are grown side by side and picked at the same time, or in factories where the herbs are packaged. Rice, starch and other compounds are sometimes added during processing to keep powdered herbs from clumping, just as kernels of rice are added to salt shakers.

But it is clear from the results that product adulteration and deliberate ingredient substitution is not uncommon as species of a lower market value are substituted for those of a higher value. This practice constitutes not only product fraud, but according to the World Health Organization, the adulteration of herbal products can be a threat to consumer safety. And as if this is not enough, pesticides and heavy metals are often found at high levels in herbal supplements, but that will be a topic of a further blog.

Consumer advocates and scientists say the research provides more evidence that the herbal supplement industry is riddled with questionable practices. But of course industry representatives argue that the problems are not widespread.

You make up your own mind.

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Beware of trans fats

No question about it. Trans fats are bad for us. Something we have known for quite some time, but not been doing that much about. Food authorities in many countries have issued warnings but hoped for voluntary action by the food industry to reduce the trans fat in their products. To a part this has also happened but not enough has been done. It is believed that current intake remains a public health concern.

A few countries, the first being Denmark, did ban trans fats, but now there is a further call for action. The Food and Drug Administration (FDA) in the USA has finally started to move by issuing a preliminary determination that partially hydrogenated oils are no longer GRAS.  That is they are not generally recognised as safe (GRAS) and will require premarket approval should the preliminary determination be finalised. This could start a ripple effect in many other countries.

So what are we talking about?

Subtle changes in fat structure - trans to the left and cis to the right (Photo: Wikimedia)

Subtle changes in fat structure – trans to the left and cis to the right (Photo: Wikimedia)

Trans fats are formed when vegetable oils are treated with hydrogen, changing their chemical composition. This process allows the liquid oil to remain solid at room temperature, preventing biscuits and cakes from going soggy and extending their shelf life. In chemical terms, trans fat is a fat molecule that contains one or more double bonds in trans geometric configuration. A double bond may exist in one of two possible configurations: trans or cis. In trans configuration, the carbon chain extends from opposite sides of the double bond, whereas, in cis configuration, the carbon chain extends from the same side of the double bond. The trans molecule is a straighter molecule. The cis molecule is bent.

The cis configuration is the natural form of unsaturated fatty acids. The process of hydrogenation adds hydrogen atoms to unsaturated fats, eliminating double bonds and making them into partially or completely saturated fats. Typical commercial hydrogenation is partial in order to obtain a mixture of fats that is solid at room temperature, but melts upon baking or consumption to make the food product taste that special extra. And in here lies the problem. Partial hydrogenation converts some of the cis configuration into trans-unsaturated fats instead of hydrogenating them completely.

And to the damage of trans fats

Sorry for the complex background but to understand the issue it is important to know what we are talking about. With the chemistry out of the way it is time to look at the bad effects of trans fats.

Various studies have over some time now linked trans fats to heart disease. A 2002 report by the National Academy of Science’s Institute of Medicine in the USA found a direct correlation between intake of trans fat and increased levels of low density lipoprotein (LDL) cholesterol, commonly referred to as “bad” cholesterol, and, therefore, increased risk of heart disease. And as if this was not enough, trans fats also lowers the levels of the high density lipoprotein (HDL) cholesterol, the so called “good” cholesterol that you actually want.

The Centers for Disease Control and Prevention in the USA estimates that a further reduction of trans fat in the food supply can prevent an additional 7,000 deaths from heart disease and up to 20,000 heart attacks each year in the American population. It is also expected that rates of diabetes, obesity, and some other ailments might be reduced as well.

Where can we find the trans fats?

Donuts (or doughnuts) often culprits with trans fat (Photo: Eric Herot)

Donuts (or doughnuts) often culprits with trans fat (Photo: Eric Herot)

More than a decade ago with the initial trans fat debate consumers started to avoid foods with trans fat and companies responded by reducing the amount of trans fat in their products. However, there are still many processed foods made with partially hydrogenated oils, the major dietary source of trans fat in processed food. Trans fat can still be found in such processed foods as crackers, cookies, cakes, frozen pies and other baked goods. Certain products such as microwave popcorn, shelf stable cakes and donuts are likely to have a higher content. It can also be found in chicken nuggets, frozen pizza, coffee creamers and vegetable shortenings.

Actually, some trans fats can be found naturally at low levels in meat and dairy products. Natural trans fats, which include conjugated linoleic acid and vaccenic acid, originate in the rumen of cattle and sheep and can comprise 2–5% of total milk and body fat. There is still debate about the harmfulness of such natural trans fats but the most convincing evidence points to their inclusion on the harmful side.

What can you do?

In waiting for further action from food authorities and the the industry there are a few things you can do. If there is compulsory label requirements you should look out for any trans fat levels declared. If not it could pay off to look at partially hydrogenated oils in the ingredient list. Thing is that products containing less than 0.5 grams of trans fats might in many circumstances be rounded down to zero. But if there is partially hydrogenated oil listed with the ingredients, there might be a small amount of trans fat. Selecting foods with even small amounts of trans fat can add up to a significant intake.

So be careful in your food choice and don’t eat donuts or microwave popcorn too often.

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