Lactase is naturally produced in the small cells that line the intestinal canal; hence any condition that affects the health and integrity of these cells can impair lactase production. We all have different levels of lactase production and hence different abilities to cope with lactose.
Food (including formula) entering the intestinal tract is broken down into smaller units that can then pass into the inner workings of the body for use. To digest food we need a huge array of enzymes and factors, occasionally some may be low or even missing, and lactase is a good example. When lactase is low (or in rare extreme cases, not present), this impedes the body’s ability to break lactose into smaller sugars (glucose and galactose). The undigested lactose continues to pass along the intestinal tract and as it goes bacteria works on it, causing a fermenting process that results in gas forming and water being drawn into the area. It is this process that leads to some of the symptoms of lactose intolerance (LI), including bloating, flatulence, diarrhoea and tummy pains.
Our production of lactase drops off markedly over our first four years. However, in some cultures where pastoral activity such as dairy farming has a long history, there appears to have been a genetic adaption over time that inhibits the slowing of lactase production. Interestingly lactose intolerance genes are not dominant genes.
Even those with mild lactose intolerance can, it seems, ‘up-regulate’ the enzymes involved in lactose digestion via continual small exposure to lactose. Basically, over time we can gain a tolerance to a certain level of lactose. Having said this, like so many things in nutrition, you can still have lactose intolerance and not show any symptoms.
If you suspect that your baby is having difficulty with the lactose in a standard formula you can have a simple breath check done (from three months of age, ask your GP for details) and if it is confirmed, talk to your healthcare professional about either a lactose-free or low-lactose formula. Keep in mind that removing lactose altogether may reduce baby’s opportunity to adapt to a level of lactose. In milk cases it may be better to try a low-lactose infant formula and when on solids, low-lactose foods in baby’s diet to allow their body to practice making lactase. In severe cases a lactose-free formula may be recommended.
Any formula noted as lactose-free must have ‘no detectable lactose’ present. Soy-based formulas, being plant-based, are free from lactose, whereas low-lactose formula must have no greater than 0.3g of lactose per 100 ml of the formula. Where a formula product uses such terms they are also required to provide information on the quantities of lactose and galactose (animal breastmilk sugar) per 100 ml.