Tag Archives: fruit

Radioactive Brazil nuts and the naturalistic fallacy


Brazil nuts. Source: Wikipedia

Believe it or not, just about all the food we consume has tiny amounts of radioactivity. Some foods contain more than others. While a small amount of it is due to nuclear fallout and industrial pollution, most of it is naturally occurring, since radioactivity is a natural phenomenon.

Brazil nuts by far are the most radioactive of all food. According to Wikipedia:

Brazil nuts contain small amounts of radium. Although the amount of radium, a radioactive element, is very small, about 1–7 pCi/g (40–260 Bq/kg), and most of it is not retained by the body, this is 1,000 times higher than in other foods. According to Oak Ridge Associated Universities, this is not because of elevated levels of radium in the soil, but due to “the very extensive root system of the tree”.

Even though Brazil nuts are a lot more radioactive compared to most foods(due to its deep, extensive roots), this doesn’t mean we should avoid them. The amount is way too small to have any permanent effects. This radioactivity in Brazil nuts is naturally occurring, not due to nuclear fallout.

Brazil nuts are an excellent source of selenium, an important mineral that some preliminary studies suggest may help prevent cancer, among other things. Fortunately, selenium deficiency is rare in most developed countries.

I think this also goes to show that eating “natural” doesn’t mean you are somehow avoiding very toxic substances. Radiation is perfectly natural, and so are lead and mercury, which are also present in trace amounts in the food and water supply. Luckily, these toxins tend to get quickly removed by the body.

While eating healthy usually means eating more “natural”(less processed foods, more whole/unprocessed foods), many health-nuts take this to extremes and buy into some form of the “naturalistic fallacy” to justify their dietary habits. This is especially true of people who follow a rawfood vegan diet, and also the followers of “paleo” diets.

At its most basic, the naturalistic fallacy means equating “natural” with being inherently good, safe, or desirable, while something “unnatural” is seen as inherently bad, or undesirable. Ask a rawfoodist to explain why they believe their diet is so much better compared to the way most people eat, and their answer ultimately boils down to: “It is more natural”. Cooked food is “unnatural”(what other animals cook their food?), so cooked food is bad; food in its raw, “natural” state is good.

This doesn’t mean there is no truth to the arguments in favor of eating raw. For instance, it is true that many nutrients are destroyed while cooking at high temperatures. On the other hand, many other nutrients are less bio-available in raw foods. It must also be noted that cooking helps destroy many anti-nutrients like oxalates or phytates that can interfere with the absorption of important minerals like iron(this is why raw spinach with its high oxalate content is a poor source of calcium and iron). This explains why you can’t eat beans raw(of course you can try to do it, but I wouldn’t advise it). While some foods like salad greens, nuts, and fruit are best eaten raw, many other foods, like legumes and grains have to be cooked.

While we should minimize our consumption of processed foods, and of both natural and synthetic toxins, we shouldn’t go overboard and panic if we discover something contains trace amounts of a toxic substance. Similarly, we shouldn’t demonize something just because it may contain something that is “unnatural”. Dogmatic black and white thinking is not helpful when it comes to healthy eating.


Radioactivity in nature

The Way of the Antioxidant

It always seemed so irresistibly simple. Oxidation = bad, therefore antioxidants = good. Free radicals(any atom or molecule that has a single unpaired electron in an outer shell, making it highly reactive and unstable) have long been seen as the “bad guys” going around our body and causing oxidative damage, by “stealing” electrons from other atoms, leading to aging and disease. This in turn can lead to a chain reaction with the atoms and molecules that had their electrons “stolen” from them becoming free radicals themselves, trying to steal electrons from other atoms.

In comes the police, uh, I mean the antioxidants to put a stop to this mayhem. Antioxidants protect the body’s tissues by donating their own electrons to the free radicals, neutralizing the threat. We actually produce our own antioxidants: glutathione peroxidase, and superoxide dismutase, among others. We also get antioxidants through our diet, such as vitamin C(ascorbic acid), vitamin E(actually a family of chemically similar fat-soluble vitamins), and beta-carotine(and other carotenoids), among so many others. Even the non-vitamin phytochemicals in many plant foods often have antioxidant effects(by definition, vitamins are absolutely essential for the body to function properly, while phytochemicals are not, though at least some of them are beneficial for health).

So taking large amounts of antioxidant supplements would obviously protect the body even more than getting smaller amounts from food, right? Wrong! Indeed, let’s look at the results of a study done on athletes who took antioxidant supplements, people whose muscles are under a great deal of oxidative stress during exercise.

Does antioxidant vitamin supplementation protect against muscle damage?
McGinley C, Shafat A, Donnelly AE.

Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland.


The high forces undergone during repetitive eccentric, or lengthening, contractions place skeletal muscle under considerable stress, in particular if unaccustomed. Although muscle is highly adaptive, the responses to stress may not be optimally regulated by the body. Reactive oxygen species (ROS) are one component of the stress response that may contribute to muscle damage after eccentric exercise. Antioxidants may in turn scavenge ROS, thereby preventing or attenuating muscle damage. The antioxidant vitamins C (ascorbic acid) and E (tocopherol) are among the most commonly used sport supplements, and are often taken in large doses by athletes and other sportspersons because of their potential protective effect against muscle damage. This review assesses studies that have investigated the effects of these two antioxidants, alone or in combination, on muscle damage and oxidative stress. Studies have used a variety of supplementation strategies, with variations in dosage, timing and duration of supplementation. Although there is some evidence to show that both antioxidants can reduce indices of oxidative stress, there is little evidence to support a role for vitamin C and/or vitamin E in protecting against muscle damage. Indeed, antioxidant supplementation may actually interfere with the cellular signalling functions of ROS, thereby adversely affecting muscle performance. Furthermore, recent studies have cast doubt on the benign effects of long-term, high-dosage antioxidant supplementation. High doses of vitamin E, in particular, may increase all-cause mortality. Although some equivocation remains in the extant literature regarding the beneficial effects of antioxidant vitamin supplementation on muscle damage, there is little evidence to support such a role. Since the potential for long-term harm does exist, the casual use of high doses of antioxidants by athletes and others should perhaps be curtailed.

Okay, so they don’t prevent oxidative damage to muscles, but can vitamin C at least improve athletic performance?

Effect of vitamin C supplements on physical performance.

Braakhuis AJ.

US Olympic Committee, Sport Performance, Olympic Training Center, Chula Vista, CA 91915, USA. andrea.braakhuis@usoc.org


Vitamin C is an essential component of the diet and may reduce the adverse effects of exercise-induced reactive oxygen species, including muscle damage, immune dysfunction, and fatigue. However, reactive oxygen species may mediate beneficial training adaptations that vitamin C attenuates; indeed, from a total of 12 studies, vitamin C in doses >1 g·d(-1) impaired sport performance substantially in four of four studies, possibly by reducing mitochondrial biogenesis, while a further four studies demonstrated impairments that were not statistically significant. Doses of ∼0.2 g·d(-1) of vitamin C consumed through five or more servings of fruit and vegetables may be sufficient to reduce oxidative stress and provide other health benefits without impairing training adaptations.

It appears that supplemental vitamin C impaired performance. The general idea here for why mega-doses of vitamin C and other antioxidant supplements are not protecting tissues or enhancing performance is that not all oxidation reactions are harmful; they are used in many metabolic reactions, for cell communications and are important for the immune system. So if you effectively shut down oxidation with a flood of antioxidants, you may be interfering with some important chemical reactions in your body, and doing more harm than good. Vitamin C isn’t just an antioxidant – it is needed for collagen production and immunity and not getting enough results in a serious deficiency disease called scurvy. Scurvy is very rare in the developed world, and only a small daily dose(60mg) of vitamin C is necessary to prevent it.

The best way to get antioxidants. Source: Wikipedia

The best way to get antioxidants. Source: Wikipedia

Okay, then maybe, just maybe a powerful antioxidant like beta-carotine can protect smokers, who are exposing themselves to a lot of oxidative damage through the act of smoking:

Beta-carotene in multivitamins and the possible risk of lung cancer among smokers versus former smokers: a meta-analysis and evaluation of national brands.


High-dose beta-carotene supplementation appears to increase the risk of lung cancer among current smokers. Although beta-carotene was prevalent in multivitamins, high-dose beta-carotene was observed among multivitamin formulas sold to promote visual health.

So far, it doesn’t look like antioxidant supplements are beneficial for anyone’s health. Beta-carotine, in particular, may even increase lung cancer risk in smokers.

This doesn’t mean that antioxidants are themselves bad for you. It just means you are better off getting them from food, where they may interact with other chemicals in the fruits and vegetables they naturally coincide with in a manner that makes them relatively harmless and likely beneficial.

Antioxidants do provide some protection, but that’s not the whole story. It’s long been thought that fruits and vegetables are beneficial largely due to their antioxidant content. This may still be true in part, but the phytochemicals in them may have other ways of protecting our health in ways science is still trying to figure out. Antioxidant content may be a proxy measure of protective phytochemical content, since many if not most phytochemicals tend to have antioxidant effects. Blueberries, with a very high antioxidant content and some possible brain-protecting effects, are a good example of this.

Good health means having a good balance between antioxidants and oxidation reactions, which taking large doses of antioxidant supplements interferes with.

Sugar – The Master of Disguise

When it comes to human nutrition, almost nothing compares to sugar. So much controversy and confusion surrounds this ubiquitous, largely maligned nutrient. Does it deserve its terrible reputation? And how many different names does sugar use these days?

Even a cursory review of sugar’s history makes it look like one of the most evil substances in human history. The institution of slavery in the Americas was founded largely to produce gargantuan amounts of sugar, to satisfy the insatiable sweet-tooths of Europeans, and nowadays food companies use sugar to get people addicted to their products. Sugar is also partially responsible for the obesity epidemic. No wonder some researchers want sugar to be classified as a drug. Also, is it a coincidence that the founder of the highly addictive Facebook, has a surname that literally means “Sugar-mountain” in German?

Obviously, it is a good idea to minimize or completely remove simple sugars from our diets, if only for our dental health. It is also highly immoral to enslave people, I do not recommend it. The links between sugar and poor dental health, and weight gain are impossible to deny.

At the same time, we all need sugar, since it is our body’s primary energy source. Sugar is a carbohydrate, and all carbohydrates are made of chains of the simplest sugar molecule, glucose, which is what all carbs are eventually broken down into during digestion.

Glucose molecule. Our primary source of fuel and the building block of all carbohydrates. Source: Wikipedia.

Glucose(C6H12O6) molecule. Our primary source of fuel and the building block of all carbohydrates. Source: Wikipedia.

The problem is that our bodies are very good at absorbing simple sugars, which I’ll come back to. In prehistoric times, back before sugar became so easily available and we were often on the brink of starvation, this was a good thing and had survival value. It didn’t just absorb quickly but we evolved to enjoy its taste so we could seek out this calorie-loaded life-saver.

Nowadays, when relatively few of us are at risk for starvation in the developed world, and we don’t have to outrun sabre-tooth tigers, this love for sugar and super-efficient sugar absorption can wreak havoc on our delicate metabolism. If consumed in excess on a consistent basis or if an individual has a genetic predisposition, it can lead to a strong insulin response that over time may cause our cells to become less sensitive to insulin(insulin resistance). Along with weight gain, this may eventually lead to type II diabetes. Insulin is needed to help cells absorb glucose from the bloodstream.

Since we still need sugar, the way around this conundrum is to consume sugar in its more complex, slow to absorb form. This is where complex carbohydrates or starches come in. These long, complex chains of glucose are difficult to breakdown, so they are slowly absorbed and don’t mess up your metabolism. Whole grains are mostly starch; candy and grape juice are mostly simple carbohydrate or sugar.

So many different types of sugar, but they are all sugar.

So many different types of sugar, but they are all sugar.

Since sugar knows it has a bad reputation, it often tries to sneak its way into our diet under a number of different disguises. Some are clever, while some are not, but it helps to be mindful of them and to realize that there really is no “healthy” form of simple sugar.

Cane juice or evaporated/dehydrated cane juice – This is just sugar. It is often used in some “health” foods to fool people into thinking it is either refined sugar-free or that it is a healthy alternative to sugar. Nutritionally, it is sugar and has all the same effects. Sure, maybe there are trace amounts of minerals in it since it is less refined than white, powdered sugar, but it is still sugar.

Brown sugar – It’s sugar, but darker!

Maple syrup – Sugar from maple trees. It’s really just liquid sugar from maple trees, the product of the sap from maple trees getting boiled down(having water removed). It is mostly sucrose, the same sugar that table sugar consists of. Often has trace amounts of minerals but it is still sugar.

Honey – Sugar made by bees. Yes it may keep better, and maybe some forms have modest benefits, but nutritionally this is just sugar again.

High fructose corn syrup – Right now, there is an epic battle going on between refined sugar(usually sucrose) and HFCS, with both of them pointing the finger at the other saying he is the more evil one. It’s rather amusing to see products at stores with the label “has no high fructose corn syrup”, yet lists “sugar” as its main ingredient.

Yet there is practically no evidence that HFCS is worse than sucrose or other simple sugars. The problem with HFCS isn’t that it is HFCS, the problem is it is sugar. So it can’t be held as uniquely responsible for the obesity epidemic, compared to other forms of sugar.

Let’s have a look at what the science says. According to Moeller SM, Fryhofer SA, Osbahr AJ 3rd, Robinowitz CB; Council on Science and Public Health, American Medical Association in The effects of high fructose syrup(J Am Coll Nutr. 2009 Dec;28(6):619-26.):

High fructose corn syrup (HFCS) has become an increasingly common food ingredient in the last 40 years. However, there is concern that HFCS consumption increases the risk for obesity and other adverse health outcomes compared to other caloric sweeteners. The most commonly used types of HFCS (HFCS-42 and HFCS-55) are similar in composition to sucrose (table sugar), consisting of roughly equal amounts of fructose and glucose. The primary difference is that these monosaccharides exist free in solution in HFCS, but in disaccharide form in sucrose. The disaccharide sucrose is easily cleaved in the small intestine, so free fructose and glucose are absorbed from both sucrose and HFCS. The advantage to food manufacturers is that the free monosaccharides in HFCS provide better flavor enhancement, stability, freshness, texture, color, pourability, and consistency in foods in comparison to sucrose. Because the composition of HFCS and sucrose is so similar, particularly on absorption by the body, it appears unlikely that HFCS contributes more to obesity or other conditions than sucrose does. Nevertheless, few studies have evaluated the potentially differential effect of various sweeteners, particularly as they relate to health conditions such as obesity, which develop over relatively long periods of time. Improved nutrient databases are needed to analyze food consumption in epidemiologic studies, as are more strongly designed experimental studies, including those on the mechanism of action and relationship between fructose dose and response. At the present time, there is insufficient evidence to ban or otherwise restrict use of HFCS or other fructose-containing sweeteners in the food supply or to require the use of warning labels on products containing HFCS. Nevertheless, dietary advice to limit consumption of all added caloric sweeteners, including HFCS, is warranted.

This is also a good read based on science: Straight talk about high-fructose corn syrup: what it is and what it ain’t.

So no, there is no evidence that high fructose corn syrup was invented by the Devil to make children obese. It is no worse nor better than other forms of simple sugar, although some suggest it may be a little more addictive.

Agave nectar – It’s very similar to HFCS. Might as well just call it “high fructose agave syrup”. Just another form of sugar. I often see this used in “health” foods, as if it’s a healthier alternative to sugar or high fructose corn syrup, but there really isn’t any significant difference.

Just about anything ending in -ose is a sugar. “Dextrose” is just another way to say “glucose”. Even concentrated fruit juice is practically sugar. Fruit is definitely good to eat, but the most sugary ones like grapes and pears are loaded with fruit sugars. Rice syrup, barley malt syrup, and molasses are also sugar syrups or come awfully close. Even many fruit juices that don’t have added sugar are just sugar water drinks.

Sugar isn’t always horrible for you. After a long heavy workout, simple sugars are a great way to refuel. And while fruit contains a lot of fructose, it also has fiber, water(assuming its not dried), vitamins, minerals and phytochemicals, so its not just empty calories. Fruit is good, just go easy on the most sugary ones.

Sugar Alcohols

On the other hand, sugar alcohols don’t cause cavities or metabolic problems, and contain fewer calories than regular sugar. One type of sugar alcohol, xylitol, is almost as sweet as sucrose(table sugar), but unfortunately it is much more expensive and can cause gas and/or diarrhea if you are not used to it. Sorbitol is another sugar alcohol. Many sugar-free gums and candies have sugar-alcohols as sweeteners. I sometimes chew xylitol gum for dental health.

Do you think you could come up with some new names for sugar, to hide that it is sugar?

Related articles: 8 Surprising Reasons Agave Is Bad for You

Blueberries the brain and synergy


Source: Wikipedia

Blueberries may be one of the best foods for keeping your brain healthy. According to research at Tufts university, Blueberry supplementation enhances signaling and prevents behavioral deficits in an Alzheimer disease model. This sounds very promising, although this study used rats instead of humans.

A study using humans at the University of Cincinnati Academic Health Center showed “The findings of this preliminary study suggest that moderate-term blueberry supplementation can confer neurocognitive benefit and establish a basis for more comprehensive human trials to study preventive potential and neuronal mechanisms.” Basically, blueberry consumption improved memory, and according to the same study “there were trends suggesting reduced depressive symptoms”.

This is quite impressive for something that often grows in bogs in the northern U.S. Blueberries tend to get a lot of attention due to their antioxidant power – if antioxidants were like muscle power, blueberries would consistently knock out all the other fruits and vegetables and be the antioxidant heavy weight champion(the only fruits that scored higher were dried so their antioxidant power became more concentrated). This antioxidant power comes from its very high amount of anthocyanins, the reddish, purplish, blueish pigments that gives it its distinctive color. However, the antioxidant effects of anthocyanins only partially explains their neuro-protective effects and other health benefits. There is so much else going on, with anthocyanins also having possible anti-carcinogenic effects. Cranberries, which are in the same genus as blueberries, have similar benefits. The bilberry is the European cousin of the North American blueberry – in Spanish however they are both called “arándano”.


Public domain image from BrainSource.com

All these studies cited(even from previous posts) only focus on one particular substance or therapy. Imagine combining them. Imagine the synergistic effects on the brain of blueberry consumption combined with exercise and juggling on patients with cognitive problems – can it also enhance brain function in people who are young and healthy? Obviously, more research needs to be done, but what we do know suggests strongly we should be eating more fruits and vegetables, especially the dark, richly colored ones.

There is so much you can do to keep your brain young, this is just the tip of the iceberg.

Related articles:

The effects of air pollution on exercise

How air pollution affects exercise performance doesn’t get as much attention as it deserves. It is a rather complex subject, although it seems rather intuitive that the more polluted the air, the worse it is for exercise. Although air pollution is everywhere, it is far worse in urban centers, with most of it coming from vehicle exhaust.

On this issue, it appears that science agrees with our intuition. According to this study – Subclinical Effects of Aerobic Training in Urban Environment, which compared people trying to improve their aerobic fitness in urban and rural settings, both groups became equally fit, though reaction times were better in rural settings and the urban exercisers had significantly higher levels of inflammation markers(exercise even in a non-polluted area can cause inflammation, it’s just worse in polluted areas).

I don’t believe the lesson to be learned from this is to not exercise if you live in a polluted area, unless you have respiratory disease, but rather to be more cautious or try to seek out an area with cleaner air to exercise if possible.

Also, I think it could be possible to prevent the inflammation caused by pollution by eating better. Some foods have a pro-inflammatory effect, like food with a high saturated fat content, as well as fried, roasted and overly processed foods. On the other hand, many fresh fruits and vegetables either have a neutral effect on inflammation or can help prevent it from getting out of control. Curcumin, a natural compound which is found in turmeric(an important ingredient in curry), has potent anti-inflammatory effects. Ginger, a close cousin of turmeric has similar benefits. Leafy greens may also help. Try to get all this from food, not supplements.

Besides this, if you are a runner living in an urban environment, try to stay far away from highways or areas with heavy traffic when running. In my personal experience, it seems that I’ve had to apply more effort when running in polluted areas than in non-polluted areas to achieve my usual pace. Also, the study I cited seems to suggest that air pollution would have more of an effect on jogglers than runners, since air pollution interferes with reaction rates/cognition during aerobic exercise. In my experience, I am more likely to drop the balls in polluted areas.

Do not let this discourage you from exercise, unless you have medical issues.