Novelist Fay Weldon’s famous advertising slogan for eggs back in the last century is being revised again.

Despite worries about cholestrol, nutritionists are now saying that eggs are one of the most nutrient-dense foods and are suggesting we need one a day for optimum health.

The study, which has been released today and will be published in June in the science journal Nutrition and Food Science, analyzed 71 research papers and documents about eggs.

Eggs are low in calories and a rich source of protein. They contain nutrients essential to good health, like vitamin D, vitamin B12, selenium and choline. They have the richest mix of essential amino acids of any other food.

Antioxidants in eggs could help prevent age-related macular degeneration, a leading cause of blindness, especially in the elderly.

Dietician, Dr Carrie Ruxton, said: “The health benefits of eggs would appear to be so great that it’s perhaps no exaggeration to call them a superfood — they are one of the most nutrient-dense foods available. Eggs are not only low in calories but are packed with nutrients that are essential to healthy living. They are an ideal food at every stage of life, as well as being easy to cook and enjoyable to eat.”

Eggs are an important dietary source of vitamin D. One egg provides more than 20 percent of the recommended daily allowance. Low levels of the vitamin have been linked with medical conditions, including poor bone health, cancer, heart disease, multiple sclerosis, immune disorders and mental health problems.

Dr Ruxton said, “There are clear nutritional benefits to eating eggs on a regular basis. Emerging evidence suggests that eggs may be beneficial for satiety, weight control and eye health. With previous limits on egg consumption lifted, most people would benefit from a return to the days of going to work on an egg.”

The work was funded by the British Egg Industry Council.

New research shows that many older people, some vegans and types of vegetarian, have a deficiency of vitamin B12.

B12 is found mainly in animal products: meat, fish, dairy and eggs. It is necessary for a variety of functions. A shortage of it has been implicated in Alzheimer’s disease.

While solid animal products can supply plenty of the nutrient, milk is said to be the better source. Up to 60 percent is absorbed by the body.

Anyone on a diet restricting meat and animal foods should drink two glasses of milk daily — skimmed milk is fine for this purpose.

The alternative is to take a good supplement that supplies more than the stated daily requirement because of the absorption factor.