Probiotics and Children’s Immunity

A recent placebo-controlled trial has found that a combination of probiotics and vitamin C helps to prevent cold infections in young children.

The study, published last month in the European Journal of Clinical Nutrition, involved 69 preschool children who each received either a placebo supplement or a chewable probiotic and vitamin C supplement for a period of six months. The study was double-blind, meaning that neither the researchers nor the children or their parents knew whether each child was taking the supplement or a placebo.

The results at the end of the six month period were promising. The children who received the probiotic and vitamin C supplement had experienced fewer upper respiratory tract infections (ie common colds), and as a result had fewer absences from preschool and fewer visits to the doctor. The probiotic and vitamin C group were also less likely to have taken antibiotics, painkillers, cough medicines or nasal sprays compared with those children in the placebo group.

Both probiotics and vitamin C are known to modulate the immune system. Vitamin C, a powerful antioxidant, reverses oxidative damage caused by infection. It is also believed to support production of phagocytes, cytokines and lymphcytes – cells that battle infection.
Healthy probiotic bacteria ramp up the body’s production of antibodies and lymphocytes, defending the body against infection (2).

In fact, around 70% of the body’s immune system resides in the digestive system which is home to around 100 trillion (about 3lbs) bacteria.

This particular study used 50mg of vitamin C alongside Lactobacillus acidophilus, Bifidobacterium bifidum and Bifidobacterium lactis strains of probiotics. Other strains of probiotics have also been linked with increased resistance to infection, though more research needs to be done in order to determine which particular strain is most effective. Hopefully this study will pave the way for larger trials to be carried out. In the meantime, probiotics have repeatedly been demonstrated as a safe supplement for children, and so trying a probiotic supplement with vitamin C would seem a sensible measure for parents of children who seem to have one cold after another.

Ideally, all children should all eat a diet which is rich in vitamin C and other anti-oxidants, and encourages growth of healthy bacteria. This means eating plenty of fruits and vegetables, and avoiding foods that deplete levels of healthy bacteria such as sugar and white grains. Unfortunately children’s sugar intake is consistently above the maximum recommended amount, and only around 10% of children in the UK manage to eat their ‘5-a-day’ requirement of fruit and vegetables (3).

Especially good sources of prebiotics – foods which feed and therefore boost probiotic bacteria – include leeks, onions, garlic, asparagus and bananas. Natural probiotic yoghurt can also help to support children’s levels of healthy bacteria. Most added sugar comes from breakfast cereals and soft drinks, and so parents should look out for these items in particular, and read labels to check from hidden sugars.

Boosting vitamin C intake and reaching the 5-a-day recommendation means adding fruits and vegetables to meals and snacks – for children, small changes such as adding blueberries to breakfast or pureeing vegetables into pasta sauces are simple changes that can make a huge difference, ensuring that children are happy and healthy both in and out of school.

  1. Garaiova, I. et al (2014) Probiotics and vitamin C for the prevention of respiratory tract infections in children attending preschool: a randomised controlled pilot study. European Journal of Clinical Nutrition.
  2. Resta SC. Effects of probiotics and commensals on intestinal epithelial physiology: implications for nutrient handling. J Physiol. 2009. 587:4169-4174.
  3. National Diet and Nutrition Survey: results from Years 1 to 4 (combined) of the rolling programme for 2008 and 2009 to 2011 and 2012. Public Health England and Food Standard Agency. 14 May 2014
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