Vitamins in milk
Fat soluble vitamins
Whole milk contains some vitamin A, however levels in semi skimmed and skimmed milks are much lower. This is because vitamin A is dissolved within the milk fat fraction which is removed to varying levels when producing lower fat milk products.
Vitamin A is required for good vision, immune health and for normal growth and development of body tissues.
Whole milk contains approximately 62µg of vitamin A per glass (200ml) which provides about 9% of an adult’s daily vitamin A requirement.
Vitamin D plays an important role in the absorption of calcium and phosphorus and is essential for healthy bones and teeth.
There are two sources of vitamin D, it is made in the skin by exposure to sunlight and there are a few dietary sources, such as oily fish, eggs, and fortified foods including margarine (which is required by law to contain vitamin D), some yogurts and breakfast cereals. There is very little vitamin D in milk and in fact only trace amounts and in the UK milk is not fortified with vitamin D.
Currently there is no dietary reference value (DRV) for vitamin D for those aged four to sixty-five years. This is because, until now, there has been a belief that exposure of the skin to UVB-rays contained in sunlight is sufficient for optimum vitamin D production. This belief was not based on solid scientific evidence.
In 2007 the Scientific Advisory Committee on Nutrition’s (SACN) report on vitamin D reinforced the need for more research before the DRVs can be reconsidered. The Food Standards Agency has funded projects, commissioned to provide evidence for the relative contributions of the two sources, dietary vitamin D and skin exposure to sunlight, to vitamin D status and to inform any future risk assessment undertaken by SACN. These projects showed low vitamin D status is a problem for some of the population in the UK and in particular for those of South Asian origin. Dietary intake was shown to make an important contribution to vitamin D status. However the research suggests that the typical daily intake of vitamin D from food contributes less than UVB rays from sunlight to average year-round vitamin status in Caucasian and Asian women.
Further appraisal of the DRVS for vitamin D will require a full risk assessment by SACN and results from the projects will need to be considered alongside other emerging research.
Vitamin E plays an important role in preventing damage to structures such as cell membranes. Substances which prevent damage in this way are called anti-oxidants and have been linked with reducing the risk of diseases such as cancer.
Vitamin E is naturally found in low levels within milk, a 200ml serving of semi-skimmed milk typically provides 0.04mg of vitamin E.
Vitamin K is essential for correct blood clotting. There is little or no vitamin K naturally found in milk although small amounts may be found in cheese.
Water soluble vitamins
Milk contains appreciable amounts of many of the B vitamins, and is particularly rich in vitamin B12.
Vitamin B12 is required for maintenance of healthy nerves and red blood cells, energy production and normal cell division.
It is predominantly found in foods of animal origin and therefore milk and dairy products are excellent sources.
1 glass/200ml of semi skimmed milk will provide an adult (19-50 years) with the full daily requirement for vitamin B12.
Exclusion of milk and dairy products from the diet can therefore significantly reduce vitamin B12 intakes. This is of particular concern when all animal products are excluded from the diet - as with the vegan diet - which can lead to vitamin B12 deficiency if suitable alternatives or supplements are not taken.
Thiamin (vitamin B1) and riboflavin (vitamin B2) are also present in milk.
Thiamin (vitamin B1) is necessary for carbohydrate metabolism, neurological and cardiac function. Unlike fat soluble vitamins, water soluble vitamins are not stored well in the body other than in small amounts, and therefore must come from the diet.
1 glass/200ml of semi skimmed milk will provide an adult (19-50 years) with 15% of their daily requirement for thiamin.
Riboflavin (vitamin B2) is necessary for the release of energy from foods and healthy membranes and skin, again riboflavin is a water-soluble vitamin and does not store in the body, and any excess amounts are excreted unchanged in the urine.
A 200ml glass of semi-skimmed milk provides 45% of an adult’s (19-50 years) daily requirement for riboflavin.
Niacin is involved in energy metabolism, the recommended amount for children and adults is 6.6mg/1000kcal and milk provides an individual with up to 3% of the daily requirement for niacin.
Folate is an important vitamin essential for cell division and correct development of tissues.
A 200ml glass of semi-skimmed milk provides a 6 year old child with 18.6% of his or her daily folate requirement and an adult with 9.3%.
It is important that women planning pregnancy consume 400 micrograms of folic acid every day before conception and during early pregnancy to prevent neural tube defects such as spina bifida.
Pyridoxine (Vitamin B6) is an essential vitamin involved in protein metabolism and is required for the formation of red blood cells and for maintaining a healthy immune and nervous system.
This vitamin is only present in small amounts in milk.
Vitamin C is required for the correct structure and maintenance of blood vessels, cartilage, muscle and bone.
Unlike other animals, humans cannot make vitamin C within the body and it must therefore come from the diet.
Good sources in the diet include many fruits and vegetables and milk also makes a contribution.
A glass/200ml of semi-skimmed milk will provide a child with 14% of the daily requirement for vitamin C and an adult up to 10.3%.