Beer : Health and Nutrition

92 Chapter Four
acids (which the human body cannot synthesise) presupposing that those proteins are
indeed taken up by the body. Meat, sh, milk and egg proteins are generally good.
Barley protein is relatively de cient in two amino acids, lysine and (to a lesser extent)
threonine, though high lysine variants have been developed (Kasha et al. 1993).
Of course most diets don’t usually contain just a solitary source of protein, and generally
there is an appropriate mix of animal and vegetable proteins.
The fats provide the essential fatty acid, linoleic acid, which the human body cannot
synthesise. Unsaturated fatty acids of this type are associated with a lower incidence of
coronary heart disease: they lower cholesterol levels. Beer is essentially fat free.
Vitamins
Vitamins are organic substances that the human body cannot synthesise itself and which
must be provided in the diet (Finglas 2003). They have various functions in the body
and are customarily divided into the water-soluble vitamins and the fat-soluble vitamins;
they are summarised in Table 4.2. For the most part they are not required in very large
quantities, but it must be borne in mind that the composition of the food matrix in which
they are present can impact on their availability. One example is the higher requirement
Table 4.2 Vitamins and their significance.
Vitamin Notes
Fat soluble
A (retinol) Not present in plants, but precursor β-carotene is, and this can be converted by human
to retinol. Shortage leads to blindness, bone/teeth failures of development; diseases of
cells in throat, nose and eyes leading to infection risk. Excess toxic
D Actually can be formed in skin by contact with light. Needed for ef cient use of
calcium and phosphate. De ciency causes rickets. Can be formed by irradiation of
ergosterol from yeast
E α-Tocopherol. Antioxidant, protecting e.g. unsaturated fatty acids and vitamin A
K Needed for normal blood clotting
Water soluble
C Ascorbic acid. De ciency causes scurvy. An antioxidant, e.g. for beer
B1 Thiamine. De ciency causes beri-beri. Sensitive to sulphur dioxide that is sometimes
used for preserving beer. Like all the B vitamins a very good source is yeast and cereal
germ and bran, e.g. from barley and wheat
B2 Ribo avin. Very sensitive to light
Niacin De ciency causes pellagra
B6 Pyridoxine. Reduces risk of cardiovascular disease and osteoporosis. No recognised
de ciency disease
Pantothenic acid Symptoms in case of shortage include depression
B12 Shortage causes pernicious anaemia
Folic acid Prevents certain anaemias
Biotin Important for healthy nails