Lactose intolerance: what’s the deal?

So, I’ve bared all about how lactose intolerance affects me.
But what exactly is it?

When we’re born, the lining of our guts are blessed with the ability to produce a digestive enzyme called “lactase”. When you ingest foods containing a complex hard-to-digest sugar called “lactose”, this enzyme helps to break down the lactose into 2 smaller, more digestible sugars, called glucose and galactose. These are then absorbed by the body and used as a carbohydrate-based fuel.

In some individuals, the ability of the guts to produce lactase decreases with age; they become “lactose intolerant” as they are unable to break down dairy into usable sugars. This is fairly uncommon in your average Caucasian Brit (5%), whose ancestors ate a dairy-rich diet and therefore developed the necessary genes to produce good amounts of lactase. In other populations however – particularly those from Africa and Southern Europe, where dairy ingestion is much less – rates of lactose intolerance can be as high as 80-100%.

When lactose passes into the large intestine in it’s indigestible state, the gut flora (bacteria) set upon it like ravenous wolves, breaking it down into various gases – hydrogen, carbon dioxide and methane.  It is these which are responsible for the embarrassing flatulence, bloating and pain associated with lactose intolerance. Additionally, because the lactose is a complex sugar which cannot be absorbed, it sits in your pipework and draws water into the guts, resulting in watery diarrhoea. Nice.

The good news is that symptoms are easily banished if enough lactose-containing foods are excluded from the diet. The exact amount depends on the individual (as some people will still produce a small amount of lactase, whilst some will produce none) and so it will be a case of trial and error as to how much can be tolerated. As a general rule of thumb, foods including milk, soft cheese and cream contain the highest amounts of lactose and may cause problems even in small amounts, whilst yoghurts and hard cheeses contain negligible lactose and may be tolerated normally. There are lots of readily available lactose free versions of milk and milk-based products, as well as nut- and plant-based alternatives (soya, almond, coconut, cashew, oat, carob…). Sheep and goat milk based foods do need to be avoided though as they also contain lactose.

Finally, if cutting out lactose in your diet helps, it’s important to consider what a diet without lots of dairy in it might mean for your overall health. Milk-based products are rich in protein, as well as important vitamins and minerals (namely calcium, vitamin D, magnesium, zinc, vitamin A and vitamin B12) which are vital for healthy teeth, bones and muscular functions among other things. So it may become necessary to take a vitamin supplement, or even see a dietitian, as well as seeking other ways to include more of these elements in your diet. Green leafy veg, nuts, lean white meat, bony fish (sardines, salmon, mackerel), soya based foods and a multivitamin are a good place to start 🙂

Lactose intolerance is fairly easy to diagnose from history alone; f you think you may be suffering, keep a food and symptom diary for a week and see your GP. Further tests are rarely needed, but may be useful if other conditions need to be excluded (e.g. coeliac disease, inflammatory bowel disease and bowel cancer). Symptoms which are NOT normal for lactose intolerance include passing blood and weight loss, so if you experience any of these, see your GP pronto!