Organic farmers are allowed to use a number of pesticides as long as they come from a natural source. Pyrethrum, an extract of chrysanthemum flowers, has long been used to control insects. The Environmental Protection Agency in the U.S. classifies it as a likely human carcinogen. There you go then, a “carcinogen” used on organic produce! Does it matter? Of course not. Just because huge doses of a chemical, be it natural or synthetic, cause cancer in test animals, does not mean that trace amounts in humans do the same. Furthermore, pyrethrum biodegrades quickly and residues are trivial. But that is the case for most modern synthetic pesticides as well! And how about rotenone? This compound was discovered in the 1800s in the extracts of the root of the derris plant. Primitive tribes had learned that the ground root spread over water would paralyze fish which then floated to the surface. Rotenone is highly toxic to humans and causes Parkinson’s disease in rats. It has been used by organic farmers to control aphids, thrips, and other insects on fruit although it is being phased out. Residues probably pose little risk to humans, but synthetic pesticides with the same sort of toxicological profile have been vilified.
Organic farmers are also free to spray their crops with spores of the Bacillus thuringiensis (Bt) bacterium which release an insecticidal protein. Yet, organic agriculture opposes the use of crops that are genetically modified to produce the same protein. Isn’t it curious that exposing the crop to the whole genome of the bacterium is perceived to be safe, whereas the production of one specific protein is looked at warily? The truth is that the protein is innocuous to humans, whether it comes from spores sprayed on an organic crop or from genetically modified crops. True, organic produce will have lower levels of pesticide residues but the significance of this is highly debatable.
A far bigger concern than pesticide residues is bacterial contamination, especially by potentially lethal E. coli 0157:H7. The source is manure used as a fertilizer. Composted manure reduces the risk, but anytime manure is used, as of course is common for organic produce, there is concern. That’s why produce should be thoroughly washed, whether conventional or organic. Insect damage to crops not protected by pesticides often leads to an invasion by fungi. Some fungi, like fusarium, produce compounds which are highly toxic. Two varieties of organic corn meal once had to be withdrawn in Britain because of unacceptable levels of fumonisin, a natural toxin.
Are organic foods more nutritious? Maybe, marginally. When they are not protected by pesticides, crops produce their own chemical weapons. Some of these, various flavonoids, are antioxidants which may contribute to human health. Organic pears and peaches are richer in these compounds and organic tomatoes have more vitamin C and lycopene. But again, this has little practical relevance. When subjects consumed organic tomato puree every day for three weeks, their plasma levels of lycopene and vitamin C were no different from that seen in subjects consuming conventional puree. In any case, we simply are not going to feed 7 billion people organically.Read more
Valentine’s Day is here and everyone is talking about love! But for many people in our modern society, a fulfilling love life also involves an active and healthy sex life. Although we have come a long way in the liberation of our minds and bodies from cultural taboos and socially imposed restrictions on our sexual attitudes and activities, we still carry with us many remnants from the past, from times when natural aspects of sexuality were frowned upon, discouraged or even demonized. Despite our recent sexual revolution, for many of us, the topics of sex and its idiosyncrasies are still difficult ones to discuss openly because of personal embarrassment or ignorance. It turns out that if we look at our sexual activity through a scientific lens that we may be able to better understand and even embrace our sexual enigmas.
The topic of masturbation, for example, is one of the most difficult ones for many to discuss... but it may actually play an important role in our sexual behaviour and have dramatic effects on male fertility.
The classic sociological explanation for why males (in particular) of most mammal species engage so readily and frequently in acts of masturbation is that it is just another form of playing or practice. Playing is a common feature of juvenile mammalian life that may act as a safe means to practice the skills that will become necessary upon becoming an adult.
In this sense, masturbation may be seen as a means to hone our skills in preparation for sex, should the opportunity arise later. Additionally, masturbation may also be a by-product of the pleasure associated with the act, which itself is an evolved feature to promote engaging in sex as an essential component of propagating the species.
Whereas these preceding explanations may certainly apply, studies of a biological nature point out that masturbation also plays an important role in maintaining male fertility by ensuring that each sperm ejected during sex has the highest potential for fertilizing the available egg.
To set the scene for understanding the journey and fate of each individual sperm cell, a little note about testicular anatomy may be in order. Human testes are divided up into several small compartments, within which are up to 800 tightly coiled seminiferous tubules that house the sperm cells as they are produced. Each tubule is so tightly packed that if they were all laid out end to end, every man would have over one and a half kilometers of sperm ducts in their scrotal sac. That’s a lot!
As the sperm are produced within the base of the tubules, they are pushed outward towards the ejaculatory duct, where they sit and wait in the epididymis for 2 weeks or so, while they fully mature to become fertile. This process is continuous, producing hundreds of millions of sperm per day and leading to ejaculates that may contain upwards of 400 million sperm. That’s an impressive assembly line, and it must make the epididymis a crowded place, as anyone who has seen Woody Allen’s film Everything You Wanted to Know About Sex can testify!
Once sperm are mature, however, their lifespan is quite limited, on the order of a few days to a week or so. Given that the production of sperm originates in the testes and pushes the older sperm to the outside, after about a week those sperm waiting to be part of the next ejaculate load may actually be infertile and useless to the reproductive aspects of sexual intercourse.
It is obvious then that males that do engage in semi-regular bouts of masturbation, may actually be cleaning out the epididymis of older, less-fertile sperm and ensuring that each ejaculate contains only the most viable and fertile ones. This would be an important evolutionary adaptation that favours successful reproduction, rather than shooting blanks, as would be the case in those males who allow a build-up and long-term storage of sperm. Interestingly, even among males who do not regularly masturbate, their bodies have a back-up plan that helps to maintain sperm viability by spontaneously expelling old loads during sleep, in a process commonly known as nocturnal emissions.
It seems, therefore, that our bodies and minds may have been primed over evolutionary time to include masturbation into our regular sexual repertoire because of the many fertility-related advantages that it may bring to our species.
Another sexual enigma that has fueled much intrigue and speculation surrounding human sexuality relates to the role of the female orgasm. Although it is clearly associated with female sensual pleasure and may act to increase their willingness to engage in sex, thereby promoting the propagation of our species, there is strong evidence that it may also play a role in enhancing female fertility.
Scientific studies that have been capable of visualizing the internal muscular contractions during female orgasm have noted that it may actually act as a uterine-pump, actively drawing up sperm deposited into the vagina and directing it towards the uterine or Fallopian tubes, where fertilization takes place. As such, although orgasms in women are not required to ensure fertilization during sex, they certainly act to make it more likely. In this way, the female orgasm can be seen as another evolutionary trait in our complex range of sexual behaviours that promotes successful reproduction in our species and even has an effect on who’s fathering whom, because those men that can induce orgasms will be more successful at fertilizing eggs in the process.
Once again, evolution has primed our species to be able to make the most of our sexual encounters in such a way that a viable and successful reproduction is the most likely outcome. Wow, being sexy is smart!
So, on this day of Love and all of its parameters, let’s not forget that the behaviours that we associate with our sexuality, mating and reproduction are all important features of being human and that these are all good reasons to celebrate with your partner (or alone) on this Valentines Day, as well as every other day of the year!Read more
When it comes to food, everyone has likes and dislikes. Chocolate generally gets favourable comments, spinach less so. But no flavour seems to elicit the degree of polarizing comments as that of cilantro. There are websites and Facebook groups dedicated to demonizing cilantro, likening its aroma to soap or curiously, to dead bugs.
The seeds of the cilantro plant are known as coriander and are even mentioned in the book of Exodus. Archeologists found some in King Tutankhamen’s tomb, perhaps placed there with hopes of adding some spice to the afterlife. The ancient Chinese believed there would be no need to worry about the afterlife if you consumed cilantro because the herb conferred immortality. Hippocrates used it as medicine and even today some people ascribe health benefits to the herb based on its content of antioxidants, anti-bacterial compounds and minerals. These, though, are not unique to cilantro, all plants contain varying quantities of these substances.
Another supposed benefit is cilantro’s ability to chelate heavy metals. The term “chelate” comes from the Greek meaning “claw” and refers to compounds that have the ability to remove harmful metal ions from solution by gripping them like a claw. Some bloggers even push cilantro as an ingredient in a “detox” salad, claiming it rids the body of heavy metals. As usual, there is a kernel of truth to the claim, but that kernel is inflated with nonsense until it pops.
A few studies have shown that cilantro leaves can produce a chelating effect in water spiked with heavy metals and that cilantro can reduce absorption of lead when food tainted with it is fed to mice. But these effects are light years from a salad with cilantro accomplishing any sort of heavy metal “detoxing” in people. Such a claim would require a demonstration of there being a heavy metal problem in the first place and its reduction with cilantro. A PubMed search for “cilantro detox” yields zero entries. Similarly, there is no basis to some food faddists’ claim that “cilantro can reduce water weight, is a cancer fighter and can improve memory with its brain protecting vitamins and minerals.”
While the scientific literature provides no evidence for health benefits, it does provide clues when it comes to cilantro’s polarizing flavour. What we refer to as flavour is the sensation triggered when molecules in food encounter receptors on our taste buds and in our nasal passage. Indeed, scent is an integral part of the sensation as evidenced by cilantro haters not being bothered if they consume the herb while holding their nose.
Some forty compounds have been isolated from cilantro including a number in the aldehyde family that are mainly responsible for the aroma and taste. The composition of the seeds is somewhat different, having linalool, also found in lavender and cannabis, as a major component. It has a pleasant floral scent accounting for its use in cleaning agents, detergents and shampoos. When inhaled it can reduce stress. At least in lab rats. Rats that inhaled linalool saw a reduction in the elevated levels of white blood cells induced by stress.
It is the aldehydes in cilantro that cause some people to liken the scent to soaps and lotions because these compounds are indeed found in those products. But why only some people? One theory is that the cilantrophobes are “supertasters” and can taste compounds that others can’t. Supertasters do exist, but they react to very specific bitter compounds such as propylthiouracil, while most people taste nothing. However, there are no such compounds in cilantro and “supertasters” are no more likely to be cilantro haters than anyone else.
It seems, though, that people ho abhor cilantro may have some sort of genetic connection, if we go by an interesting study carried out by Dr. Charles Wysocki of the Monell Chemical Senses Center in Philadelphia. Taking advantage of the annual twins festival in Twinsburg, Ohio, Wysocki had identical and fraternal twins rate the scent of chopped cilantro. There were definitely lovers and haters, with identical twins almost always agreeing with their sibling, which was not the case for fraternal twins. Experiments at Monell have also separated the components of cilantro using gas chromatography and showed that while everyone can smell the “soapy” aldehydes, cilantro haters cannot smell the compounds that make the herb so attractive to its fans.
Interestingly, there is also an ethnocultural connection. A study at the University of Toronto surveyed 1639 young adults and had them rate their preference for cilantro on a 9 point scale. East Asians were the most likely to dislike cilantro with roughly 21% expressing their distaste. Caucasians were not far behind at 17%. Only 14% of those of African descent disliked the taste, followed by South Asians at 7%, Hispanics at 4% and Middle Eastern subjects at 3%. These stats roughly parallel the use of cilantro in the cuisine of these areas suggesting that there is a connection between liking cilantro and frequency of exposure.
While cilantro’s enemies would rather stick rusty needles into their eyeballs than eat the fresh herb, they normally don’t object to cilantro in cooked foods such as pesto. That’s because the herb’s flavor changes as the volatile aldehydes escape into the air when it is crushed, cooked or pureed. Cilantro fans of course crave fresh cilantro and when cooking add the herb at the end stage. As for me, I’m with Julia Child on this one. Back in 2002 she told Larry King in an interview that if she found cilantro in a dish she was served she would pick it out and throw it on the floor. I recognize, though, that there are people who would jump to catch it before it hit the ground because they just love the smell and taste of this herb that has pleased some and irritated others since biblical times.
The term "base" derives from an age old observation that the residue from a wood fire has certain chemical properties. This mixture of minerals and ashes, or as it came to be known, the "base" of the fire, could destroy the acidity of vinegar or react with fats to produce soap. Today, we know that the "active ingredients" in the fire residue are hydroxides of potassium and sodium. hese chemicals, although they are no longer isolated from ashes, are widely used today as "bases." Sodium hydroxide, or lye, as it is commonly known is one of the most important industrial chemicals. In addition to its role in soap manufacture, it is used in aluminum processing, in the pulp and paper industry and in the manufacture of numerous other chemicals.
Around the house sodium hydroxide can be used to open clogged drains ("Drano"). It is so caustic that it can actually break down the accumulated deposits of fat and hair. Obviously it can have a similar effect on human skin and must be used with great caution. Most oven cleaners are also based upon sodium hydroxide. hese decompose baked on fat and convert it into soluble soap. Dilute solutions of lye are used as general cleaning agents around the kitchen.
Bases can of course be used to neutralize excess stomach acid. Calcium carbonate ("Tums"), magnesium hydroxide ("Milk of Magnesia") aluminum hydroxide ("Amphojel") and sodium bicarbonate ("baking soda") are common over-the-counter remedies for hyperacidity, or "heartburn" as it is generally known. On a larger scale, bases such as calcium hydroxide, or lime, have been used to neutralize the excess acidity in lakes introduced by acid rain. Now you know the “base”ics Read more
I'm no alarmist when it comes to "artificial chemicals" used in food or cosmetic production.But I do question the use of colourants because they have no function other than changing the appearance of a product. Why do we need mouthwash to be blue? It's because somehow people have been conditioned to associate blue with cleanliness, which is why window cleaners, toilet bowl cleaners and mouthwashes are blue.
The colourant most commonly used is "Brilliant blue #1," not one of the synthetic dyes that was associated with hyperactivity in children in the famous University of Southampton study that implicated six colours and started the scampering to replace synthetic colours with natural ones. Brilliant blue can in rare cases cause allergies, but that is true for almost any substance, natural or synthetic, with which we come into contact.
Colours isolated from natural sources, such as betanin from beetroot or carmine from the cochineal beetle undergo the same stringent approval process as do synthetic colours, but testing for hyperactivity is not one of the criteria. Industry prefers synthetic colours because in general they are less susceptible to changes in pH and are more stable when it comes to exposure to light or oxygen. Although allergic reactions to colours are rare and the hyperactivity connection is certainly not iron-clad, why not educate people not to expect brilliantly coloured products?
The industry would probably argue that in the case of mouthwash, if it were colourless, people would think they are being duped into buying water. That brings up the question of why we need mouthwash in the first place. But that's another story for another time. Just one more thing...replacing Brilliant blue #1 in blue Smarties by phycocyanin isolated from blue-green algae does not make them smarter to eat.