Current studies suggest that women are far superior to men when it comes to tasting and smelling. Is this true and how does our sense of taste actually work?
Men must be able to can smell and taste better than women. Surely this is why there are far more men who are top chefs, winemakers and sommeliers than women?
But is this really true? The clear answer is no. At least not according to the latest studies. More and more studies are in fact proving the opposite. A few years ago, Brazilian researchers found out that women react much more sensitively to smells than men and can also remember certain scents better. The explanation; according to a study published in the scientific journal, PLOS One, women have almost 50% more nerve cells in their olfactory bulb than men. The somewhat uncharming term 'olfactory bulb' refers to the structure in the front of the brain that transmits olfactory signals from the olfactory mucosa in the nose to those parts of the brain where odour perception takes place.
"It seems reasonable to assume that the larger number of neurons enables women to have a better olfactory performance," says Roberto Lent from the University of Rio de Janeiro.
Sensory sex differences
An elaborate study conducted a few years ago supports this thesis. A research group led by neuroscientist Madhura Ingalhalikar from the University of Pennsylvania in Philadelphia examined almost 1,000 volunteers with a brain scanner in order to explore the course of the nerve fibres in the brain using diffusion tensor imaging (DTI). Among other things, it turned out that the two hemispheres of the brain are more strongly connected on average in women than in men. According to the scientists, this suggests that, on average, women show significantly better results than men when it comes to smelling and recognising tastes. Also, there are clear anatomical differences in the structure of the noses between the sexes, especially in the volume of the nasal cavities. Furthermore, there may be genetic reasons that could be responsible for the sensory gender differences.
Genes and taste
Although the human sense of taste has been studied scientifically for quite some time, further recent studies have revealed more precise correlations. It is becoming increasingly clear that the sensitivity for the perception of taste stimuli is genetically determined and varies from person to person. In fact, not everyone's taste is equally intense; some people like or are irritated by what others do not perceive at all.
Pioneering work in the field of taste research was done by the American Linda Bartoshuk from the University of Florida, who has been investigating the mysterious world of taste for several decades now. She developed a test in which volunteers were administered a chemical called propylthiouracil (PROB), a bitter substance that is perceived differently by different people. Since then, she has distinguished between three categories of tastes: the 'super-tasters' (also called PROB-tasters), 'normal tasters' and 'non-tasters'.
Bartoshuk discovered that super-tasters have a special gene on chromosome 7. Such sensitive palates have a larger arsenal of taste buds and therefore more taste buds and taste cells than others. Super-tasters have an average of 420 taste cells per sq cm on the surface of their tongue. Normal gourmets, on the other hand, have an average of 180 of these cells and non-tasters just 100.
Several studies have shown, however, that only a quarter of the world's population belong to the super-gourmets, another quarter are non-gourmets, while the majority are classified as normal gourmets. Scientists also found that more women than men belong to the super-gourmets and that the proportion of this group is far higher in Asia than in Europe and the US.
However, supertasters are not automatically a naturally privileged group of hedonists, gourmets and foodies. On the contrary, their highly developed sense of taste may often spoil their enjoyment. Super gourmets with their special genetic make-up often dislike foods such as grapefruit, chicory or other vegetables because they contain overtly bitter substances.
"Super-tasters are often over-sensitive when it comes to food and find many things unpleasant that others enjoy," believes US scientist Bartoshuk. That is why, in her opinion, most top chefs and wine experts tend to fall into the category of normal gourmets. Only with the so-called non-tasters is the matter particularly simple: "These people," says the taste researcher from Florida, "may react with only a shrug even to the best risotto in the world."
Taste qualities
Currently, six taste qualities are considered scientifically recognised: sweet, sour, salty, bitter, umami and for a while now, also fatty. Special fat receptors were first discovered in animal experiments in 2005; before that, it was believed that high-fat food was only perceived through smell and texture. Umami, on the other hand, discovered by Japanese researchers, is a protein with the taste of the amino acid MSG (monosodium glutamate). In terms of meaning, umami is akin to savoury or flavourful; in the western world, this flavour component is found in beef soups, for example.
The preference for sweet and umami is innate and makes perfect evolutionary sense. Sweetness, for example, is closely linked to our need for carbohydrates – an important source of energy for humans. Infants have an innate aversion to bitter and sour tastes – an evlutionary function that has evolved to protect them against ingesting poisonous plants, which usually taste bitter.
For a long time, it was assumed that only the tongue was responsible for taste perceptions of all kinds. But taste buds are also located in the palate, in the oesophagus and on the inside of the cheeks. The former division of the tongue into individual taste regions is generally considered outdated, as recent studies have shown, the entire surface of the tongue registers all taste variations.
Tasting is not infrequently a deception devised by nature. Those who are convinced that they can taste hot spices in certain dishes are mistaken. In fact, pungency is not a taste, but a sensation in the mouth that is reported to the brain as a corresponding signal. The surprising thing is that the intensity with which the brain reacts to spiciness is clearly genetically determined, which is why everyone perceives spicy foods and spices differently.
The biggest misconception about tasting, however, relates to a very specific organ: the nose. What gourmets and connoisseurs love to rave about when they taste a delicious truffle dish, roast duck or an aromatic fish soup is not so much due to the work of the taste sensors. In fact, the smell of the food is incomparably more important. "What we colloquially refer to as taste is actually a multi-layered mixture of several factors, the most important of which is the perception of odours," writes American biologist Rachel Herz in her book The Scent of Desire.
According to the world's leading expert in the study of the sense of smell, the aroma of food is perceived twice during eating: once through the nose when the morsel approaches the mouth (orthonasal olfaction), and a second time when it has long been in the mouth. This retronasal olfaction takes place when the smells of food and drink travel from the oral cavity to the pharynx and nasal cavity. From there, the information is passed on to the central nervous system, with part of it reaching the limbic system in the brain. This area of the brain is responsible for emotions, amongst other things. Not only do the nerve pathways of the sense of smell end here, but this is also where the distinction is made as to whether a taste quality is perceived as pleasant or unpleasant.
All in all, research is now certain that olfactory perception is incomparably more important in tasting than gustatory perception. By the way: Since the overall olfactory perception decreases significantly with age, older people generally taste less intensively than younger people.
Despite the constant flow of new findings in the field of taste research, it should not be overlooked that specific taste preferences and the question of whether someone wants to be considered a foodie or a fast-food junkie are to a large extent the result of upbringing, experience, social environment and not least the food culture of their respective country. The majority of Chinese, for example, reject the taste and smell of cheese because it makes them think of spoiled milk.
Accordingly, the assumption that people can judge taste objectively has long been disproved. The best example: British chef Heston Blumenthal of the three-star restaurant The Fat Duck, west of London, liked to mislead his guests in terms of taste years ago. The chef with a penchant for molecular cuisine once served his astonished guests a beetroot jelly to which he had added a little tartaric acid. This created a sour taste. If this idiosyncratic 'dessert' was called redcurrant jelly, unwitting guests were thrilled. However, if the waiters told the guests that it was beetroot, the reaction was completely different: Everyone was suddenly sure that "the wobbly stuff was particularly disgusting".
