You Asked: Blueberries and Milk

blueberries and milk“I put blueberries and milk on my cereal in the morning. Which one should I give up?” That was the question I received via email. A reference was included to a study about the antioxidant activity of blueberries being impaired when consumed with milk, as well as one about milk consumption being linked to greater risk of bone fractures and to earlier mortality. While both these studies appeared in the peer-reviewed literature and are interesting, their practical significance is questionable.
The milk study focused on people drinking more than three glasses of milk a day and could not rule out “reverse causation,” namely that some subjects were drinking more milk because they already had risk factors for osteoporosis. As far as earlier mortality goes, the authors suggest it may be linked to an inflammatory effect attributed the galactose, a breakdown product of lactose, the sugar found in milk. But this is pure conjecture. It is also possible that people who drink a lot of milk have a higher calorie intake or a lower vegetable intake, or exercise less, all of which can be confounding factors. Milk may not be as important a dietary component as Canada’s Food Guide suggests, but there is no need to avoid it. Moderation is the key.

Blueberries are widely perceived as “healthy” based upon their content of antioxidants. These naturally occurring substances are found in numerous fruits and vegetables and are thought to be responsible for the benefits attributed to a diet that contains lots of plant products. Laboratory investigation can determine the antioxidants present in food but to what extent they are absorbed into the bloodstream is a more difficult question. We don’t eat single food components, we eat food. Studies have shown, for example, that polyphenols, a family of antioxidants found in tea, are more poorly absorbed when milk is added to tea because proteins in milk bind to the polyphenols. The blueberry study aimed to investigate the fate of two particular antioxidants, namely caffeic and ferulic acid when consumed with or without milk. Eleven subjects, a very small number in terms of scientific studies, consumed 200 grams of blueberries either with 200 mL of whole milk or 200 mL of water. For two days prior, the subjects were asked to abstain from foods containing antioxidants including all fresh fruits and vegetables as well as tea, coffee, juices, wine and chocolate. This unrealistic eating pattern already adds confusion to the study.

In any case, analysis of the subjects’ plasma indicated a somewhat reduced antioxidant content when the blueberries were consumed with milk. This has little relevance to health. Blueberries are not commonly consumed with milk, except perhaps when they are eaten together with cereal. And there is no compelling evidence that the antioxidant content of plasma is a determinant of health. Furthermore, the plasma’s antioxidant potential is determined by the overall content of the diet and is not going to be affected to any significant extent by the handful of blueberries added to cereal whether consumed with or without milk.

 

Joe Schwarcz

 

Let’s face it-creams deliver more hype than evidence

creamsIn the 1980s, Dr. Albert Kligman, an American dermatologist  made an interesting observation.  Patients being treated for acne with retinoic acid saw an improvement in their wrinkles, an improvement that was eventually traced to enhanced collagen formation. But there was a but. There were hurdles on the road to smooth skin. Retinoic acid treatment resulted in increased sensitivity to sunlight, and initially, in irritated skin. To ensure that patients were properly monitored, retinoic acid was made available only by prescription. But cosmetic producers are free to include other forms of vitamin A, such as retinol, in face creams. At the concentrations used, however, the effect of retinol is minimal.

Pentapeptides, now heavily marketed as anti-wrinkle agents, emerged from a study on wound healing. Researchers investigating the nature of the chemicals used by cells to trigger the formation of collagen identified these messengers as short chains of five amino acids, in other words, “pentapeptides.” Laboratory studies of skin tissue soon showed that collagen formation could indeed be enhanced, but there was a question of pentapeptide absorption through the skin. Linking the pentapeptides to a fatty acid such as palmitic acid yielded absorbable “palmitoyl pentapeptide,” the “active” ingredient in many an anti-wrinkle cream.  The claim is that constant use over twelve weeks results in firmer, more youthful skin. Maybe so. If you look with a microscope.

Glycosaminoglycans, usually referred to as GAGs, are naturally occurring compounds that help the skin retain moisture and resilience. Can their production be increased? Apparently, xylose, a simple sugar, can stimulate the production of GAGs. The problem is delivering it to the appropriate cells. Just adding xylose to creams won’t do, but xylose precursor compounds that can be absorbed from creams have been developed. Once inside cells, these yield xylose, which in turn fires up GAG formation. This is not just theory, skin biopsies actually show increased amounts of GAGs. But does this translate to improved appearance? In a double blind clinical trial, treatment with a xylose releasing cream resulted in better skin elasticity, less dryness, fewer age spots and reduced wrinkles. The problem, though, is that these measurements are made by technicians using sophisticated instruments. Whether the difference is going to cause heads to turn is debatable.

Also debatable is the effectiveness of antioxidants in creams. In theory, they should do something. In practice, there is no compelling evidence that they do.  The newest players in the antioxidant sweepstakes are “nanoparticles” composed of “fullerenes,” molecules made of sixty carbon atoms joined together in the shape of a soccer ball. Indeed, fullerenes are effective at neutralizing free radicals, but safety questions have been raised about what nanoparticles may do when absorbed into the body. Probably about as much as they do in a cream.

 

Joe Schwarcz

When it comes to insomnia, there’s no shortage of advice

insomniaO sleep! O gentle sleep!

Nature’s soft nurse, how have I frightened thee,

That thou no more wilt weigh my eyelids down

And steep my senses in forgetfulness?

Henry IV is not one of the Bard’s most memorable plays. I think it once lulled me to sleep. But these lines speak of insomnia, a common problem that begs for a solution. There is no shortage of advice. Count sheep. Drink warm milk. Feast on turkey. Take melatonin pills. Take kava-kava. Try valerian root. Mix up a drink from a special powdered blend of pumpkin seeds and dextrose. Listen to recordings of chirping crickets. Settle down on a mat embedded with amethyst crystals. Relax on a “Polar Power Mega-Field Slumber Pad” designed by Dr. William Philpott whose last name rhymes with a term that can be used to describe his ideas about treating disease.

Virtually all diseases, Philpott maintained before he left us, could be managed or reversed with magnet therapy. Of course you had to have the right type of magnet. Only those that were capable of producing a “negative magnetic field” were therapeutic since “only these can promote an oxygen-alkaline rich environment within the body.”

That environment doesn’t come cheap. Philpott’s miraculous pads are still being sold for hundreds of dollars. But instead of focusing on the claptrap of negative magnetic fields, let’s look at something that may actually have a positive effect. Like that mixture of pumpkin seed powder and dextrose.

First, we need to do a little travelling back in time to the 1970s and the lab of MIT neuroscience professor Richard Wurtman. Unlike Philpott’s random ramblings, Wurtman’s research is backed by hundreds of peer-reviewed publications that have established him as one of the world’s leading authorities on chemical activity in the central nervous system.

It was Wurtman who demonstrated that levels of the neurotransmitter serotonin in the brain respond to dietary manipulation. This is of importance because higher serotonin levels have been linked with anti-anxiety effects, appetite suppression and sleep enhancement.

Serotonin is formed inside cells from the amino acid tryptophan, a component of most dietary proteins. When some questionable info emerged about turkey containing high doses of tryptophan, the lay press was ready to jump. Turkey became a remedy for insomnia and even made an appearance on a Seinfeld episode in which Jerry and George conspire to put Jerry’s current girlfriend to sleep by overdosing her on turkey so that they can play with her collection of antique toys.

Actually, turkey protein does not have more tryptophan than other meat proteins. In any case, as Wurtman demonstrated, tryptophan levels cannot be increased by eating more protein. That’s because amino acids are ferried across the blood-brain barrier by transporter molecules that have less of a preference for tryptophan than for the other amino acids that make up proteins.

However, should a tryptophan-containing food be coupled with a source of carbohydrates, levels of tryptophan in the brain, and consequently serotonin, will rise. This happens because carbohydrates stimulate the release of insulin, which prompts the absorption of amino acids into muscles.

But here, too, tryptophan is absorbed less efficiently, meaning that with the competing amino acids being driven into muscles, more tryptophan is available for absorption into the brain. Eating a turkey sandwich, with the bread providing the required carbs, actually makes some sense.

While serotonin may have a calming effect, it doesn’t actually induce sleep. The hormone melatonin, however, does. And it is made in the brain’s pineal gland from serotonin. This reaction, however, is inefficient as long as the eyes are stimulated by light. But with darkness, conversion of serotonin to melatonin begins and drowsiness sets in. The formula for sleep would then appear to be coupling darkness with a source of tryptophan and a carbohydrate that stimulates quick insulin release.

Wurtman’s research prompted Canadian psychiatrist Craig Hudson to investigate the possibility of a commercial product designed to increase melatonin levels. He knew that melatonin supplements were available, but evidence indicated that when taken in a pill form, the hormone has a short half-life. Hudson’s idea was to try to induce a normal sleeping pattern with a more continuous release of melatonin.

First, he needed a good source of tryptophan and found it in the seeds of a specific variety of pumpkin. He then mixed the powdered seeds with glucose, the archetypical insulin releaser. A bit of natural lemon or chocolate flavour, and “Zenbev” sleep-enhancer was born. It hit the market after a double-blind placebo-controlled clinical trial showed that subjects with sleep problems were able to reduce the time spent awake during the night. Admittedly, a single study is not very compelling, but there seems to be no risk giving Zenbev a shot.

Neither is there a risk, outside of a possible allergy, in eating two kiwifruits an hour before bedtime. That’s right, kiwis may help with sleep problems. In a study of 24 subjects, sleep onset, sleep duration and sleep quality were significantly increased with kiwi consumption.

But why study kiwis at all in this context? It turns out that the fruit is a source of serotonin. Although the authors declare no conflict of interest, they do acknowledge support from Zespri International Ltd. A quick Google search reveals that Zespri is a marketer of kiwifruit. That of course does not invalidate the study, but it would be comforting to see the trial duplicated by a totally objective research group. In the meantime, there’s no harm in giving the kiwi regimen a shot. Serotonin aside, kiwis are a great source of antioxidants and folate.

And if Zenbev or kiwis don’t lull you to sleep, you can indulge in a cup of decaffeinated Counting Sheep Coffee. It contains valerian root extract, which does have a history of use as a sedative. During the Second World War in England, it was even used to relieve the stress of air raids.

But as far as this coffee goes, we just have to take the marketer’s word for its sleep-inducing effect. That, though, coupled with an appearance on television’s Dragon’s Den, seems to have been enough to perk up sales.

And that should make the investors in Counting Sheep Coffee sleep better.

Joe Schwarcz

Soft drink bottles are made of a plastic called polyethyleneglycol terephthalate, or PET. While this plastic is fine for storing soft drinks, why is it not recommended for storing home-made wine?

While PET has a very low permeability when it comes to carbon dioxide, it readily allows oxygen to pass through. And oxygen is the enemy of wine! When we talk about storing soft drinks, permeability to carbon dioxide is the critical factor. A beverage that loses carbonation loses its appeal. In this case oxygen permeability is not an issue. While oxygen passing into a plastic soft drink bottle from the air may react with some of the flavor components, the effect would be minor given that we don’t store soft drinks for extended periods. But of course we do store wine to age it. And this is where oxygen becomes a problem. Grape juice contains a variety of compounds called polyphenols which can react with oxygen and produce a variety of colors and flavors. This really is the same chemistry that occurs when an apple is cut and exposed to the air. Reaction between polyphenols and oxygen produces the brown discoloration. Not only will the apple slices look different, they will also taste different. The same thing can happen with wine. White wine is more susceptible to such changes because it lacks some of red wines colored compounds, the anthocyanins, which can act as antioxidants. Sulfur dioxide is also an effective antioxidant, which explains why compounds such as sodium bisulfite are used to preserve wine. Burning sulfur inside wine barrels to produce sulfur dioxide is an age-old method of preservation. Now back to our plastic bottles. As we have seen, empty soft drink bottles are too permeable to oxygen and are not appropriate for storing wine. But wine can be purchased in plastic containers, although I suspect a true eonophile would look warily upon this method of marketing. So how do the marketers solve the problem of oxygen permeability? By sandwiching a layer of an oxygen-impermeable plastic between layers of food-grade polyethylene or polypropylene. Ethylene-vinyl alcohol copolymer is ideal for this purpose since it allows very little oxygen to pass through. A bit of ingenious chemistry. So while it is not a good idea to store your wine in old soda bottles, it is quite acceptable to purchase wine in plastic containers.

Joe Schwarcz

What is all the talk about “Paradox Blanc?”

wineIf you take a look at all the literature put out by the French wine industry, you’ll start to wonder whether you should replace wine drinking by intravenous infusions of red wine. They make a case for wine being virtually a drug to prevent heart disease. They offer reams of scientific evidence about neutralizing free radicals and preventing cholesterol from damaging the walls of arteries. Of course, that doesn’t prove that wine is responsible for the French Paradox. That paradox is the low rate of heart disease compared to North America in spite of a high fat diet.

Red wine may indeed be part of the answer because the skin of red grapes contains compounds called polyphenols which do have antioxidant properties and which may prevent cholesterol from being converted into a damaging form. But what about people who favor white wine? This has a far smaller antioxidant capacity than red wine. Leave it to French ingenuity though. A team of wine researchers at Montpelier University have come up with a Chardonnay that has almost the same antioxidant potential as red wine. They found that if the grapes were macerated with the skins and seeds and the fermentation temperature increased, the polyphenol content of the wine increased dramatically.

Furthermore, these scientists managed to show that the wine really has an effect on the antioxidant potential of the blood. They destroyed some of the insulin producing cells in the pancreas of rats to make the animals diabetic. This is because diabetes is known to reduce the antioxidant capacity of the blood. Then they administered the new Chardonnay to the critters for six weeks and found that the antioxidant capacity was restored. Who says laboratory rats don’t lead good lives? The special polyphenol enriched Chardonnay will be available soon to humans as well. So those of you who prefer white over red will be able to ask for “Paradoxe Blanc.” Of course the real paradox is why people just don’t eat more fruits and vegetables which have more antioxidants than red or white wine!

Is there a difference between synthetic and natural vitamin C?

vitaminThe properties of a substance are determined by the structure of its component molecules. Vitamin C that is synthesized in the laboratory has exactly the same atoms joined together in exactly the same fashion as vitamin C that is made in an orange or a rose hip bush. As far as biological activity goes, the source of vitamin C is irrelevant. The cheapest version is as effective as the most expensive.

Perhaps a more appropriate question is whether we should be taking vitamin C supplements. There is a wealth of information suggesting that the human body benefits from vitamin C in excess of the roughly 20 mg daily needed to ward off scurvy. Population studies show that people who consume the most vitamin C from foods have reduced incidence of certain cancers, particularly stomach cancer. This likely reflects vitamin C’s ability to reduce the formation of nitrosamines, known cancer causing substances. In a study that encompassed 65 counties in China, blood samples from randomly selected adults were analyzed for vitamin C. Those who had the highest levels were the least likely to develop cancer.

Furthermore, it has been found that the vitamin C level in the white blood cells of cancer patients is unusually low and that the plasma vitamin C level of smokers is 43% lower than of non-smokers. This may explain why children of smokers have a greater risk of genetic diseases such as leukemia. Bruce Ames, one of the leading cancer researchers in the world, discovered that sperm damage in men increases as vitamin C levels in the body drop. He discovered that below a daily intake of 60 mg, there is measurable damage to the DNA in sperm. Surveys show that half of all men of reproductive age consume less than this amount of vitamin C daily. If they are smokers, the problem is of course exacerbated.

The antioxidant effect of vitamin C may also provide protection from heart disease. In the test tube, vitamin C can prevent the oxidation of LDL cholesterol; this oxidation has been linked with damage to coronary arteries. Epidemiological studies appear to bear out this observation. A study at the University of California analyzed the diet of 11,348 adults ranging in age from 25-74 in the early 1970’s. Ten years later, men who had the highest intake of vitamin C had a 45% lower rate of heart disease. In a corroborating study, 747 Massachusetts residents who were 60 or older in the early 1980’s had blood samples taken. A dozen years later, the heart disease rate was lowest among those who had the highest blood levels of vitamin C. The blood levels correlated with eating vegetables high in vitamin C.

There seems to be no doubt that vitamin C can help guard our health. It is even important in the functioning of vitamin E, which is oxidized in the process of carrying out its antioxidant activities. It is then reduced to its active form by vitamin C. But what is the optimal daily intake? The most comprehensive study to try and answer this question was carried out in 1996 at the National Institutes of Health in the US. Seven healthy young men agreed to live in a hospital ward for up to half a year. Their blood levels of vitamin C were depleted by putting them on a very low vitamin C diet. Then they were given doses of 30 mg, 60 mg, 100 mg, 200 mg, 400 mg, 1000 mg and 2500 mg a day to determine which dose would result in peak amounts in the blood and tissues. Doses greater than 200 mg per day did not increase vitamin C levels in the blood or tissues. At 1000 mg, oxalate began to show up in the urine indicative of the breakdown of excess vitamin C. The ballpark figure for optimal vitamin C intake was therefore judged to be in the 200-500 mg range daily. Since some of this comes from food, a supplement of 200 mg a day seems appropriate.

Can there be any harm from vitamin C supplements at this dose? Most unlikely. Larger doses can cause diarrhea and cause a false negative result in fecal blood tests. They may also increase the risk of kidney stone formation through oxalate and can also enhance the absorption of iron from food which may be a problem for people who have undiagnosed iron overload disease, known as hemochromatosis. But no studies have shown any harm in the range of 200 mg a day.

Going all the Whey

Little miss muffet sat on her tuffetWill Whey “Buff you up”?

“If everyone ate whey, doctors would be bankrupt”, or so goes an “old Italian saying”. Whey does have many healthful properties and its consumption has shot up so much that producers are scrambling to meet the increasing demand. What is all the fuss about anywhey?

Once upon a time, Hercules set a very particular trend. With unbeatable force and bulging muscles, Hercules set the standard for every modern body builder. While Herc got his bulk by wrestling with bulls and fighting three-headed dogs, his modern imitators are less diligent and more impatient: they seek something that will make them bigger and stronger faster .

Muscles are made up of proteins which are polymers of amino acids. When you exercise, you burn energy that was stored in your body. If you want to burn fat and not muscle, it is important that you maintain your muscles by supplementing your diet with protein, in order for your body to get the building blocks (the amino acids) it needs. Otherwise, your muscle themselves will be digested as you exercise, thwarting your efforts. Since vegetables contain less protein on a weight per weight basis than meat, one rarely hears of vegetarian body builders.

Though soy and other legumes are a fairly good source of protein, they do not compete with red meat and egg. Until recently, egg white was the all-time favourite protein source, since excessive red meat consumption has been connected with health problems. These days, though, whey is by far the protein champion.

Whey is the watery concentrate left behind after a cheese curdles. The curds themselves are a mixture of fat and protein, mostly casein. Whey contains among other things the protein alpha-lactalbumin, vitamins and minerals. It is particularly rich in the essential branched chain amino acids (leucine, isoleucine, and valine) and the biochemically vital cysteine. Essential means our bodies cannot produce these compounds so we must obtain them from our diet.

When whey is undenatured, that is, when the protein has not been heated to the point of changing its original 3-D molecular conformation, it is the best source of protein for your muscles possible. That is not to say, however, that ingesting whey protein will make your muscles burst into growth. No evidence exists to this effect, in spite of all the hype surrounding “pump you up” whey protein formulas on the market. Resistance training will make your muscles larger, whey will only ensure that your body has what it needs to make the necessary expansion. Clinical trials on HIV+ women showed that a combination of regular resistance training and whey consumption significantly slowed the process of “wasting”, the rapid reduction in lean body mass typical of AIDS.

The whey debate really only applies to very, very serious athletes and body builders. Most healthy, active people are already getting much more protein daily than their body needs to maintain or even build muscle mass. Only if you spend most of your time exercising should protein source be a serious concern for you, so long as your diet is balanced. It should be noted, however, that there is some evidence suggesting that calcium (found in whey and all dairy products) has the ability to inhibit adiposity (fat storage), favouring a shift toward a leaner body composition.

By the Whey…

Besides being an excellent source of protein, whey offers other interesting benefits. Of late, it has been celebrated as an antioxidant, an immune-builder and even a mood-stimulator. The immune response to toxins and pathogens in the body depends on the rapid proliferation of lymphocytes, a kind of white blood cell. Glutathione regulates these frontline defenses by stimulating lymphocyte production. Glutathione synthesis in the body depends on the presence of the amino acid cysteine, an amino acid that abounds in whey protein. Whey formulas that have high cysteine content have shown a measurable effect on immune response in immunosuppressed individuals such as the HIV positive or people suffering from chronic fatigue syndrome (CFS). Whey’s capacity to build the immune system reinforces its appeal for athletes who may suffer from immunosuppression as the result of intense physical exertion. So far, whey is the only practical vehicle for cysteine, N- acetylcysteine being an emetic (causes nausea) and pure cysteine being toxic at the required levels.

Furthermore, there is some preliminary evidence showing that certain whey formulas may reduce the incidence of cancerous tumors and slow their growth. The explanation for this observation comes from whey’s ability to decrease cancer cells’ glutathione levels. Though this may seem to contradict whey’s ability to increase glutathione concentration in healthy cells, the difference rests on a negative feedback mechanism whereby glutathione would inhibit its own synthesis when it is present at high levels. In cancer cells, glutathione levels are so high that anti-tumor drugs are often ineffective against their rapid proliferation. Consuming whey might be one way to reduce tumor cells’ defense, making chemotherapy much more effective.

Whey also has antioxidant properties since glutathione is involved in inactivating oxygen free radicals. Free radicals are highly reactive species with an unpaired electron that wreak havoc on the body by causing oxidation of chemical bonds in DNA and important enzymes. These processes are thought to lead to cancer, heart disease and the neurodegeneration associated with aging. Glutathione peroxidase and peroxide dismutase are two enzymes that inactive these harmful species and these are both activated by the compounds present in whey extract.

Finally, whey contains tryptophan, a synthetic precursor for serotonin, the neurotransmitter responsible for good mood and relaxation. Some scientists have suggested that for this reason whey may have mood-elevating properties. Indeed, people consuming whey report feeling happier, but perhaps this is only a product of their satisfaction in doing something healthy and positive for themselves. Only time will tell…

Lauren Lapointe-Shaw

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