|Zinc and the Zinc Taste Test
Zinc is an essential trace element. It is one of the most important of the trace elements needed by the body. Of the many hundreds of protein enzymes present in the body, which allow its chemistry to work, zinc is required by over two hundred of them. It can thus be seen how a deficiency of zinc can affect so many different functions (see below).
Zinc is also important in the production of prostaglandins (PGs). PGs are vital to numerous body functions including, for example: the function of the immune system; the expression and control of inflammation; skin and wound healing; function of the heart and cardiovascular system; absorption of various minerals; body temperature control and the important functions of fertility, conception, and delivery of the infant.
The way in which zinc influences PG production is by potentiating (or supporting the function of) the enzymes which permit the conversion of the polyunsaturated fatty acids into PGs. Zinc thus has a very direct action in stimulating the normal production of PGs thereby maintaining or restoring normal health and fitness.
Zinc is of vital importance in MS and other auto-immune diseases, partly because of its effect in promoting the production of PGs but, more importantly perhaps, because, by acting in its capacity as an antioxidant co-factor in the enzyme, superoxide dismutase, it helps maintain the integrity of the essential fatty acids that contribute to the regeneration of the myelin.
Zinc deficiency can result in many symptoms, including: loss of appetite, growth retardation, diarrhoea, tremor, hair loss, dandruff, a dry skin rash, white lines on fingernails, increased allergic sensitivity, disturbance of menstrual periods, pre-menstrual syndrome, delay of wound healing, loss of taste or smell sensation, dyslexia, poor night vision, photophobia (sensitivity to light), depression, sleep disturbance, hyperactivity, reduced fertility, loss of sex drive, pre-eclampsia (toxaemia) of pregnancy and post-natal depression.
It has been observed that those suffering with any of the auto-immune diseases (such as multiple sclerosis, rheumatoid arthritis, psoriasis, etc); atopic problems (allergy, eczema, asthma or migraine); or many of the inflammatory diseases (such as osteo-arthritis, ME or irritable bowel syndrome), have a consistent, and often severe, zinc deficiency, which is greatly benefited by a programme of zinc replacement therapy.
Zinc supplements in MS will increase both energy and vitality, increase muscle strength, improve sleep and prevent fatigue. Perhaps in company with vanadium, another common mineral deficiency in MS, which contributes to the occurrence of depression, it will also prevent this distressing symptom.
The zinc taste test is used to evaluate this common state of deficiency. This simple and non-toxic test was devised and developed by Professor Derek Bryce-Smith, Professor of Biochemistry at Reading University. Professor Bryce Smith is an established authority on zinc and numerous other biochemical topics.
The test solution is zinc sulphate in purified water, at a concentration of 1 gramme/ litre.
Once prepared the solution should be stored in a refrigerator and discarded after six months. The solution should be removed from storage and left at room temperature for about two hours before carrying out the test.
The test is based on the knowledge that the functions of taste and smell are dependent upon there being sufficient zinc available in the body. Thus, if zinc is deficient then taste function will be diminished. This principle is utilised in the taste test by offering a standard test solution of zinc sulphate for tasting. The response is then compared with a series of defined standards and the zinc status thus determined.
The test involves taking a sip of the solution (approximately 5-10 mls - using the beaker supplied) and holding it in the mouth for ten seconds, timed with a watch. Due to the possible influence of recently consumed food or drink on the taste experienced it is essential that neither be taken for approximately one hour before the test.
The defined standards are:
Grade one response: no specific taste sensation: tastes like plain water. This indicates a major deficiency of zinc requiring a supplement of at least 150 milligrammes (mg) of zinc per day.
Grade two response: no immediate taste is noticed but, within the ten seconds of the test, a `dry' or `metallic' taste is experienced. This indicates a moderate deficiency requiring a supplement of 100 mg of zinc per day.
Grade three response: an immediate slight taste is noted, which increases with time over the ten second period. This indicates a deficiency of minor degree requiring a supplement of 50 mg per day.
Grade four response: an immediate, strong and unpleasant taste is experienced. This indicates that no zinc deficiency exists. If this is the response to the first test done then obviously the diet already contains sufficient zinc and no supplement need be taken.
If this is the response, however, after a period of zinc supplementation then the diet, prior to the supplement being given, must be assumed to have been deficient. Thus, if a relapse to this deficient state is to be further prevented a regular maintenance dose of zinc is required. One 15-20 mg dose per day is usually sufficient for this purpose.
During any period of supplementation the taste test should be repeated at appropriate intervals and the subsequent dose of zinc adjusted according to the above instructions. In addition, it should be noted that when starting any programme of zinc supplementation, the starting dose should always be a minimum dose of 15-25 mg. This is then increased slowly in the following manner stopping at the required level as demanded by the results of the taste test.
Thus in the first week: take one 15 mg (or 25 mg) dose per day.
Second week: two 15 mg (or 25 mg) capsules or tablets per day.
Third week: one 50 mg dose per day.
Fourth week: two 50 mg doses per day.
Fifth and subsequent weeks: three 50 mg doses per day.
The reason for this protracted introduction is that zinc treatment, in the presence of zinc deficiency, may initially induce a feeling of fatigue or depression: a slow introduction reduces this possibility.
Zinc should be taken each day after food. If unusual tiredness occurs during the initial stages of treatment it should be taken at night before retiring to bed. In this way it will benefit any difficulty in sleeping and promote increased vitality the following day.
Various zinc preparations may be used, including possibly chelated zinc, zinc citrate, zinc picolinate, or zinc gluconate. Zinc sulphate is the most common (and cheapest) presentation but should be avoided due to the frequent occurrence of gastric irritation and dyspepsia. To avoid such a possibility, as a precaution, any zinc preparation should be taken after food. The most efficiently absorbed is the chelated form. This is where the zinc is combined with an amino acid, which assists in its absorption.
High doses of zinc (50 mg/day or more) should also be accompanied by a small dose of copper. This is because a large amount of zinc in the diet will compete with, and reduce the absorption of, copper. It therefore becomes necessary to take a regular supplement of copper to prevent a state of copper deficiency developing. The appropriate dose of copper is 2 - 4 mg per day. This single dose is usually all that is required whatever the dose of zinc used.
High doses of zinc will also tend to reduce the absorption of iron. This is not usually a problem but, in strict vegetarians, when the intake of iron is low, there may be a need to take a small, regular dose of iron to prevent the occurrence of iron-deficiency anaemia.
Please address any questions regarding the use of zinc, or the zinc taste test, to the address shown below.
Dietary Research Limited, 10 Heol Gerrig, Treboeth, Swansea, West Glam SA5 9BP
Telephone: 01792 – 417514; Company Registered Number 2615367