Soy foods and breast cancer risk

It is well known that Asians tend to have a lower breast cancer risk, both in their homelands, and in the U.S. The exact reasons for this are not clear, but it is theorized that high soy consumption among Asians may be at least partly responsible for the decreased risk. According to the Keck School of Medicine, University of Southern California, Los Angeles in Epidemiology of soy exposures and breast cancer risk:

Abstract

Most of the early studies published on soy and breast cancer were not designed to test the effect of soy; the assessment of soy intake was usually crude and few potential confounders were considered in the analysis. In this review, we focused on studies with relatively complete assessment of dietary soy exposure in the targeted populations and appropriate consideration for potential confounders in the statistical analysis of study data. Meta-analysis of the 8 (1 cohort, 7 case-control) studies conducted in high-soy-consuming Asians show a significant trend of decreasing risk with increasing soy food intake. Compared to the lowest level of soy food intake (<or=5 mg=”” isoflavones=”” per=”” day),=”” risk=”” was=”” intermediate=”” (or=”0.88,” 95%=”” confidence=”” interval=”” (ci)=”0.78-0.98)” among=”” those=”” with=”” modest=”” (=”” approximately=”” 10=”” day)=”” intake=”” and=”” lowest=”” ci=”0.60-0.85)” high=””>or=20 mg isoflavones per day). In contrast, soy intake was unrelated to breast cancer risk in studies conducted in the 11 low-soy-consuming Western populations whose average highest and lowest soy isoflavone intake levels were around 0.8 and 0.15 mg per day, respectively. Thus, the evidence to date, based largely on case-control studies, suggest that soy food intake in the amount consumed in Asian populations may have protective effects against breast cancer.

An autumn hike and some sassafras tea

On one of my days of rest from running last week, I went for a little hike in a wooded area near me, enjoying that early autumn coolness. The leaves are still stubbornly holding on to their greenness, but they will eventually change into all sorts of brilliant colors within a few weeks as the temperatures fall and the days get shorter.

As much as I enjoy the fresh air and greenery of a hike, I also venture out into the wilderness to see what Mother Nature has to offer me. As I often like to say, if you can identify edible wild plants, a hike in the woods can be like a visit to the supermarket.

Sassafras growing on the edge of the woods

Unfortunately, my favorite wild mustard greens are all dead; so are most other wild greens. Fortunately, sassafras grows plentifully in this area, and I’m in the mood for some spicy tea. Sassafras is usually a small to medium sized tree, and saplings are common in this area. Believe it or not, during the colonial era, sassafras was one of America’s biggest exports to Europe.

Sassafras is easy to identify, due to how it produces 3 different types of leaves: one with 3 lobes, one with 1 lobe so it looks like a mitten, and one that is oval shaped. Very few plants in the north-eastern U.S are like this. If you can’t identify it by sight, you can try cutting off a little section of leaf or twig and smelling it. It will smell sweetly aromatic, sort of like cinnamon to me.

Sassafras root

Although you can make tea from any part of the sassafras plant, the roots pack the most punch.

Luckily the soil was kind of loose so it was easy for me to dig up some sassafras root with my hand.

Sassafras tea

I brought it home, cut it up and then put in some water to boil then simmer it for 20 minutes. I then poured the sassafras water through a strainer into a tea cup. It tasted amazing, it’s very soothing, tasting sort of like cinnamon or even ginger at times.

It’s a pleasant tasting tea, but I don’t know if it has any medicinal effects, beyond some mild anti-fungal and anti-bacterial properties. Sassafras for the longest time was one of the main ingredients in root beer, but I will explain below why this is no longer the case.

The potential carcinogenicity of sassafras

Sassafras contains safrole, which according to animal research is a carcinogen. I think everyone should be made aware of this, even if the evidence for harm in humans isn’t especially strong. According to an article in the Los Angeles Times, Sassafras is Safer Without Safrole:

Research: In the 1950s and ’60s, researchers showed that high doses of safrole caused liver damage and liver and lung cancer in mice and rats that were fed the compound for long periods of time. Nursing mice developed tumors when their mothers were given safrole. Because human studies are lacking, researchers don’t know what dose might cause cancer in adults or children. (Safrole occurs naturally in many spices, like nutmeg, but in amounts tiny enough to be considered harmless.) Although lab experiments show that safrole has antifungal and antibacterial properties, no clinical research has provided evidence for its — or sassafras’ — supposed health benefits.

Based on other things I’ve read, root beer makers can still use sassafras so long as the safrole is removed. Since I drink sassafras tea about once every 4 years, and in small amounts, I don’t think I have a whole lot to worry about. This post isn’t necessarily a recommendation to drink sassafras tea; you can still enjoy the fragrance on hikes or even use it as an air freshener, but there are a million other herbal teas you can safely drink that may even have some medicinal effects.

This site has some interesting information on sassafras, suggesting the cancer risk is overblown – Safrole is not nearly as dangerous as you would think

If anyone reading this is a chemist, I would love to know what you think about the cancer-causing potential of sassafras. How dangerous is it?

The mighty flaxseed

It is for good reason that many people sing the praises of flaxseeds. I’ve even written songs about them; some people may love to sing about red wine or cocktails, but I prefer singing about flaxseeds.

Source: Wikipedia

They are a very healthful addition to any diet, due to their unique nutritional contents that are difficult to get elsewhere. Not only are they a great source of fiber, but they also contain the essential fatty acid ALA, and also contain lignans which have phyto-estrogen effects.

Flaxseed has a lot of ALA(alpha-linolenic acid), which is one of the 3 main types of omega 3 fatty acids which are essential for the body’s metabolism. The 2 other types of omega 3s, EPA(eicosapentaenoic acid) and DHA(docosahexaenoic acid), are not found in flaxseed, but are plentiful in fish oil. The body has a very limited ability to convert ALA to EPA or DHA, so we are better off getting it through diet. Omega 3s are important because they help suppress inflammatory processes that may be damaging to the heart or other organs. The benefits of DHA are so widely recognized that many food companies fortify their products with it. DHA and the other omega 3s are particularly important for pregnant and nursing women, since DHA is needed for optimal brain growth.

If we look at a randomized, controlled study of omega 3 and omega 6 supplementation on children reported in Pediatrics. 2005 May;115(5):1360-6. – The Oxford-Durham study: a randomized, controlled trial of dietary supplementation with fatty acids in children with developmental coordination disorder.

“No effect of treatment on motor skills was apparent, but significant improvements for active treatment versus placebo were found in reading, spelling, and behavior over 3 months of treatment in parallel groups. After the crossover, similar changes were seen in the placebo-active group, whereas children continuing with active treatment maintained or improved their progress.”

This study wasn’t about flaxseed per se, but did use a fatty acid that is found in flaxseed. Flaxseeds may be helpful for preventing prostate cancer:

“Findings suggest that flaxseed is safe and associated with biological alterations that may be protective for prostate cancer. Data also further support low-fat diets to manage serum cholesterol.”

This is really impressive, and this just involves the omega 3s in flaxseed. The lignan content of flaxseeds are a whole other exciting ball game. Flaxseeds are by far the best source of lignan, containing hundreds of times more than almost all other plant foods. Lignans are phyto-estrogens(similar to the phyto-estrogens in soy) and may help prevent breast cancer, according to research done at Linköping University, due to their powerful hormonal effects. They may not only lower blood estrogen levels but may also lower testosterone levels. The testosterone lowering effect may concern some men, but I don’t think it is a cause for alarm based on the evidence. More research is obviously needed, but I’ll continue to sing about them in the mean time.

The best way to eat flaxseeds is to ground them yourself in a small coffee-grinder, or to use the oil as a supplement or salad dressing. Never use the oil for cooking, omega 3s aren’t heat stable. Flaxseeds also contain significant amounts of protein and minerals. No wonder many people call it a “Super Food”.

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.
Source

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

Abstract

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.
Source

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

Abstract

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

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.

CONCLUSIONS:

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.

Sitting may be dangerous for your health

Sitting may be dangerous for your health, according to some studies. I know, I know, you’re probably sick of hearing how certain everyday habits may cause disease, but this is a health and fitness blog so it’s totally on topic.

Anyway, sitting is associated with an increased risk for many different diseases, even in people who exercise every day yet sit a lot during work or leisure. Excessive sitting may play an important role in the obesity epidemic and may also partially explain the Tofi phenomenon, people who are Thin on the Outside but Fat on the Inside.

The simple solution is to simply move around more, and if you must sit, to get up every now and then to stretch or do some quick exercises. I often stand at my desk when blogging or browsing, but not always. Sitting on an exercise ball may be a little better; stand up desks or treadmills seem like a great solution. It’s disturbing how sitting seems to be as bad as smoking when it comes to health, at least according to some research.

Whatever you do, keep moving!

Is Sitting a Lethal Activity?