Hot dogs still have it licked
QUESTION How do furry animals get enough vitamin D?
Vitamin D is made up of a group of steroid-like molecules and unique in that it is the only vitamin that can come from a non-food source, namely sunshine. it regulates the absorption of calcium and phosphorus in the body, and is involved with calcium mobilisation from bone.
One major way in which animals differ is in whether they obtain vitamin D from sunlight or from food. it was thought sunlight doesn’t penetrate fur and that when UV light interacts with oils in the skin, dogs lick the vitamin off and swallow it.
in fact, dogs and cats are unable to convert much vitamin D in their skin when exposed to UV light, and they derive practically all their vitamin D from food sources.
However, fur is not a barrier to vitamin D absorption in other animals. a 2010 Danish study looked at ‘vitamin D(3) synthesis in the entire skin surface of dairy cows despite hair coverage’.
in an experiment, four groups of Holstein dairy cows were covered with fabric. as in humans, the more of their body that was covered up, the lower their serum vitamin D levels.
Researchers concluded that fur does not block UVB as clothing does.
Dr Ian Smith, Cambridge.
QUESTION Is the idea that specific areas of the tongue detect specific tastes — bitter, sweet etc — a fallacy?
taste is the body’s first line of defence against poisoning — it tells the brain whether or not to swallow what’s already in the mouth.
We’re born loving sweet and hating bitter, because natural sugar is brain fuel, while bitter is the sensory cue for poison.
tastebuds were detected in the 1800s by German scientists Georg meissner and
Rudolf Wagner, and their discovery paved the way for the next step in taste research, which was determining the mechanisms by which taste cells work.
For years, every basic biology text perpetuated the claim that tastebuds are grouped in the mouth according to specialty: sweetness at the tip of the tongue, sourness on the sides and bitterness at the back.
But in the eighties, chemosensory scientists revealed that the ‘tongue map’ was a misinterpretation of German research.
it has its roots in a 1901 paper, Zur
Psychophysik Des Geschmackssinnes, by David P. Hanig, who found variation around the tongue in how much stimulus it took for a taste to register.
He measured the thresholds for taste perception around the edges of the tongue by dripping stimuli corresponding to salty, sweet, sour and bitter tastes in intervals around the edges of the tongue.
Different parts of the tongue have a lower threshold for perceiving certain tastes, and the tip and edges of the tongue are particularly sensitive to tastes, as they contain many tiny sensory organs.
When Hanig published his findings, the line graph he included of his measurements was more of an artistic interpretation than an accurate representation.
it plotted the relative change in sensitivity, yet the illustration made it look as though different parts of the tongue were responsible for different tastes, rather than showing some parts were slightly more sensitive to certain tastes than others.
it’s now agreed that taste is not as straightforward and tastebuds aren’t grouped according to specialty and aren’t confined to the tongue, either — they’re everywhere, from the roof of the mouth to the throat and stomach. sweetness, saltiness, bitterness, savouriness and sourness can be tasted everywhere on the palate. and although one person might experience sourness in some places on their palate more than in others, that’s part of their genetic make-up alone. Emilie Lamplough, Trowbridge, Wiltshire.
QUESTION In the 1929/30 football season Brentford FC won all 21 home matches. Has this feat ever been repeated?
FURtHeR to the earlier answer, while Brentford won every home game in the old Division three south, in the 2010/11 season man Utd came close to being the only other top-flight team (sunderland 1891) to win every home game.
a draw against West Bromwich spoilt the record, which finished W18 D1 L0. their away record was not so hot: they were the first team since 1912 to win the league, yet win only five away games.
Dave Warner, Fleckney, Leics. in tHe 1929/30 season Brentford’s home goals record was 66 for and just 12 against, but they were still not promoted from the then Division three south.
this was because of their poor away form. in those days you gained only two points for a win and one point for a draw.
Lindsay Harverson, Brentford, W. London.
IS THERE a question to which you have always wanted to know the answer? Or do you know the answer to a question raised here? Send your questions and answers to: Charles Legge, Answers To Correspondents, Daily Mail, 2 Derry Street, London, W8 5TT; fax them to 01952 780111 or email them to charles.legge@dailymail.co.uk. A selection will be published but we are not able to enter into individual correspondence.