Nutrient - Cell nucleotides and health
Until recently, cell nucleotides were not considered important nutrients because it was assumed that we could produce enough of them to meet our requirements. However, there is now highly suggestive evidence that dietary nucleotides are extremely important to our health. It appears that these nucleotides may even contribute to keeping our digestive and immune systems in tip-top condition.
What are nucleotides?
Nucleotides are among the basic building blocks and blueprints for life. They are naturally-occurring compounds found in all living cells of the body, and play major roles in almost all biological processes. Each nucleotide consists of three parts: a sugar molecule, a phosphate molecule and a structure called a base.
How are nucleotides obtained?
The cells in our body can produce nucleotides from “scratch” or salvage them from dying cells. Dietary nucleotides, as the name suggests, come from our diet, and represent a small but significant component of the diet – typically one to two grams of nucleotides per day in an adult. Nucleotides are naturally present in all foods of animal and vegetable origin. Some foods are higher in nucleotides than others, but in most normal foods, the amounts are quite low. Good dietary sources include fish, poultry, liver, meat, yeast extracts, some peas and pulses and mushrooms.
Most infant formulas contain supplemental nucleotides, which are found naturally in human breast milk. They are added with the aim of enhancing the gastrointestinal and immune systems of formula-fed infants.
Nucleotides are also added to some “immunonutrition” formulas, which are immune-enhancing tube feeding formulas, used in critically ill and surgical patients.
Why are nucleotides so important?
Nucleotides participate in numerous biological processes and play key roles in the normal functioning of our cells. First and foremost, nucleotides are the building blocks of RNA and DNA, which are the basis of the replication of living things. In addition, nucleotides serve as a source of energy for the cell, and also help some enzymes to do their job. When nucleotides are released outside of the cell, they play important roles as chemical messengers that allow cells to “talk” to their neighbours.
Cells are the basic units of life. To continue to live, grow and develop, new cells need to be produced to replace dying and damaged cells. To create new cells requires energy and a healthy supply of nucleotides to build the RNA and DNA molecules in the new cells. It was initially thought that dietary sources of nucleotides were generally not necessary for normal growth and development, and that the body was capable of producing all the nucleotides it requires. However, this idea has been punctured by research publications, which have shown that dietary nucleotides are extremely important and a deficiency may impair gut and immune function. Hence supplementation may be appropriate in certain situations.
Nucleotides: effects on intestinal and immune health
The rapidly dividing cells of the immune system and those lining the intestines have little ability to synthesise their own nucleotides, but have a high requirement for them. In addition, producing nucleotides requires a lot of time and energy, and is limited during stressful situations. Therefore, a dietary source may help to support and optimise the function of the gut and immune system.
Nucleotides have been shown to be important for normal growth, development and repair of the intestine. The lining of our intestine has folds and small finger-like projections called villi. These folds and villi allow for a greater capacity to digest and absorb nutrients.
Nucleotide supplementation has been shown, in studies, to support the natural replacement of cells forming this lining, and the regeneration of the villi. The intestinal lining also represents a vast frontier of body surfaces that need defending. As a result, the intestinal lining has an immune system, which is focused on maintaining a healthy gut. Dietary nucleotides have been shown to help support the function of this immune system.
Dietary nucleotides have been shown to positively influence growth and function of immune system cells, including those that help fight infections (lymphocytes), those that kill infected cells (natural killer cells), and those that eat pathogens and dead cells (macrophages).
Exciting scientific observations have also demonstrated the ability of nucleotides to help restore normal immune function following malnourishment, and support natural resistance to infection by the human pathogens, Candida albicans and Staphylococcus aureus.
Clinical studies have reported beneficial effects of nucleotide-enriched formula milk on infant health, including improved antibody response following immunisation, reduced incidence and duration of diarrhoea, and increased production of interleukin-2, an immune-stimulating protein. Nucleotide supplementation may support healthy growth in formula-fed infants. These studies also suggest that the nucleotides naturally present in human milk may contribute to some of the benefits associated with breast-feeding.
The bottom line on dietary nucleotides
Dietary nucleotides offer an evidence-based strategy for supporting gut and immune system health, especially during times of stress or illness. Their addition to infant formula milk and tube-feeds clearly demonstrates a consensus in the scientific community that nucleotides are important for health.
Dietary nucleotides are indeed an exciting area of nutrition research, and one that will most likely continue to attract considerable interest for a very long time.