Could a Food Incompatibility be Spoiling Your Life? 19
Plants may also contain hormone-like substances. Oestrogen
precursors are found in yams. Goitrogens are substances causing goiter
(swollen neck due to thyroid enlargement). Soya bean extract includes
significant amounts and goiters have been seen in human infants fed with
soya milk (iodine appears to counteract this effect, so infant soya milks
are fortified with iodide as a precautionary measure). Goitrogens are a
common constituent of plants belonging to the Crucifer family (cabbage,
turnip, swede, broccoli, cauliflower, kale, Brussels sprouts, rape and mustard
seed).
Hypertensive substances are amino compounds such as serotonin
and noradrenalin (norepinephrine), which constrict blood vessels and
thereby elevate the blood pressure. Such substances occur in chocolate,
pineapple juice, avocado, alcohol and cheese.
This is by no means an exhaustive list but sufficient to make the
reader realize that there may be a problem, even if nobody has told you
before. The real mystery is not so much why people are sometimes made ill
by food toxins, so much as why isn’t everyone made ill, all the time? (I’ll give
you one important answer further down.)
Poisoning may come into food indirectly. An endemic goiter seen
in Tasmania is probably due to milk from cows fed on kale and turnips.
A disease known as milk sickness, characterized by weakness, nausea and
collapse, has occasionally reached epidemic proportions in certain parts
of the USA (it probably caused the death of Abraham Lincoln’s mother).
The name derives from the fact that the disease is brought on by drinking
milk from cows made ill with a disease known as the trembles. This was
eventually tracked down to the consumption, by cattle, of a plant known as
snake root (Eupatorium rugosum), containing the chemical tremetone. Along
the same lines, a poison in lupin has been known to be transferred to human
beings via goat’s milk.
Plant alkaloids
One very important group of plant chemicals are the alkaloids. These are
small organic molecules, usually comprising several carbon rings with side
chains, one or more of the carbon atoms being replaced by a nitrogen
(which confers the alkalinity). About seven to ten per cent of all plants
contain alkaloids, of which several thousand are now known.
Famous alkaloids include caffeine, nicotine, quinine, strychnine,
ergotamine and atropine. The less toxic ones, such as caffeine, are used for
pleasant social effects or as hallucinogens (cannabis and peyote).