Liver Consumers

Those who regularly consume liver (lamb’s calves pig’s etc) or live products such as pate will receive very substantial amounts of retinol as well as copper and as a result supplements containing these nutrients may be not only unnecessary but may be harmful.

Retinol
The liver, including that of humans, is a storage organ for vitamin A in the form of retinol. Growing animals are fed supplements containing retinol as their rapid growth rates means that they have high demands, which may not always be met by their food supply.  As a consequence their livers contain high levels of retinol and if these are eaten regularly an intake above the Safe Upper Level of 1500 ug per day may be easily achieved.
The Scientific Advisory Committee on Nutrition, SACN, issued a report
Review of Dietary Advice on Vitamin A. September 2005
http://www.sacn.gov.uk/pdfs/sacn_vita_report.pdf
The report advised that;

• No supplements of retinol if liver is eaten once per week or more
• Those who consume liver once per week should not increase their intake
• Excess retinol is likely to manifest itself as osteoporosis
• Industry
• Farming

In addition I would also advise that;

• Others at risk may include regular/heavy alcohol consumers, older people, those with renal impairment, and possibly those with abdominal obesity
• Headache, raised blood calcium (hypercalcaemia) and scalp hair loss may be features of retinol excess
• A more cautious recommendation for the consumption of liver is to restrict it to once per month with the exception of chickens’ livers which could be consumed up to once per week. 
  Those most likely to require and benefit from vitamin A in the UK are infants aged between one and a half and four and a half years but it is usually their grandparents who are consuming it.

Information on Dietary Sources of Retinol [internal link]

Nutrient Content of Animal Liver per 100 g

Copper
Live is also a major source of the trace element copper.  Regular consumers of liver would have a high intake of this element but are unlikely to exceed the Guidance Level of 10 mg per day for this trace element unless they were also taking supplements.  However a study of nutrient intake and cognitive decline [internal link] in elderly subjects in Chicago found a higher rate of decline in those with a high intake of both copper (from food and supplements) and saturated animal fats.
It may thus be prudent for older people with or at risk of cognitive decline, who also have a significant intake of saturated fats (from meat, cheese and other dairy foods) to limit their intake of high copper content foods (liver and whelks).
Those with the very rare metabolic disorder, Wilson’s Disease, which results in copper accumulation, are also advised to limit their intake of liver and other copper-rich foods.

Information on Dietary Sources of Copper [internal link]