The following script is based on an article I wrote for the Allergy & Free From show magazine last year. With some updates!

What is lactose?

Lactose is a sugar, for this sugar to be used by us, the walls of our lower digestive system produce a digestive enzyme called lactase. This enzyme helps to break down the sugar so it can be made small enough to be taken into the body and used as energy. See the above infographic.

What causes lactose intolerance?

Congenital lactose intolerance occurs because of the gut not being able to produce any lactase enzyme from birth – this is very rare. Primary lactose intolerance is where the gut loses the ability to create the lactase enzyme over time. Secondary lactose intolerance can occur with a digestive disease, gastrointestinal infections and food poisoning, which may or may not be short term.

Some people’s ethnic background puts them more at risk of lactose intolerance because in South America, Africa and Asia, over half of the indigenous population have primary lactose intolerance and in some Asian countries almost everyone can have primary lactose intolerance.

What symptoms might I have?

The symptoms from lactose intolerance can be unpleasant and embarrassing and range from loose, watery poo, wind, bloating and a distended tummy. Some people get stomach cramps, loud digestive gurgling noises, feeling sick and occasionally are sick. These symptoms occur because undigested lactose in the bowel pulls fluid from the body as it moves through the lower digestive tract, causing diarrhoea. Then lactose is then used for energy by the bacteria usually found in the bowel – this causes bloating and wind.

When do I need to see my doctor?

Usually, digestive symptoms because of food poisoning are often quick to resolve (lactose intolerance after a digestive system infection usually resolves after six weeks), if you still struggle with symptoms, see your doctor, don’t be tempted to self-diagnose. Don’t be shy in talking about your symptoms – doctors have heard them all before. You can always write down your symptoms before you go if you just find them too difficult to talk about.

The following symptoms are not expected with lactose intolerance if you have swelling of your lips, mouth or face; rashes or wheezing within minutes to a few hours of drinking milk. This might suggest an allergy – see your doctor. Or, alternatively, blood mixed in your poo with a temperature and feeling unwell. These are not symptoms generally associated with lactose intolerance and may be due to another medical problem.  Contact your GP and don’t make drastic changes to your diet.

All children should be seen by their doctor and lactose intolerance because of cow’s milk protein allergy should be considered. Because babies and young children are more vulnerable, any symptoms of blood or mucus in poo, green vomiting, a temperature and severe tummy pain in young children call NHS 111 for advice or discuss with your doctor urgently.

What tests are available for lactose intolerance?

No blood tests can identify lactose intolerance. Sometimes your doctor might advise a test called a hydrogen breath test – but often they will recommend following a full lactose-free diet for one month and then introduce lactose to test that symptoms return, which is usually very useful in identifying this intolerance. Testing food is also essential to find your own level of lactose tolerance. Most people can have a small amount without having any symptoms at all, and this knowledge can make following a lactose-free diet a little bit easier. A registered dietitian can help you do this effectively and check you are getting the correct nutrition from your modified diet.

Might symptoms be caused by something else?

Occasionally, it’s possible to have lactose intolerance along with other digestive complaints, such as:

Coeliac disease (autoimmune gluten enteropathy) this is because gluten, a protein in wheat, barley and rye, damages the bowel surface so it cannot make the lactase enzyme very well. See your doctor, and your doctor will complete tests for coeliac disease if it is suspected. It is vital to continue to eat food containing gluten to make quite sure that the tests used can identify coeliac disease well. Lactose intolerance usually resolves with treatment for coeliac disease.

A few people with inflammatory bowel disease (IBD – Crohn’s disease and ulcerative colitis), which causes the bowel wall to become swollen and ulcerated, can also occasionally have problems digesting lactose. Due to inflammation of the bowel wall sometimes it cannot make the lactase enzyme very well. This lactose intolerance can resolve with treatment for IBD.

People with irritable bowel syndrome (IBS) can have problems digesting lactose, this might occur because of the gut microbe fermentation of some foods (called FODMAPs.) Lactose is a FODMAP. FODMAPs are sugars found widely in the diet that are poorly digested and result in symptoms for people with IBS. If you wish to try a low fodmap diet ask your doctor for a referral to a registered dietitian to help you. Don’t be tempted to exclude all carbohydrates from your diet. Wholegrain starchy carbohydrates are essential for long-term gut health.

Where is lactose found?

In animal milk, some cheeses, some yoghurts, processed foods made from animal milk and some medications. Most medications contain tolerable amounts so don’t stop taking them. Discuss alternatives with your doctor or pharmacist if you are taking a few medicines containing lactose, as this might be enough to cause symptoms.

Lactose-containing ingredients can be recognised on the food package ingredients list by the following words – milk, lactoglobulin, milk solids, buttermilk, lactose, artificial cream, whey powder, cheese, condensed milk, curd, skimmed milk powder, cream cheese, modified milk, evaporated milk, margarine and butter. As milk is an allergen, it will be listed as bold, in italics or in a different font or colour on the ingredients list. But lactose is not an allergen as such, so it doesn’t need to be listed separately to milk. Lactose-free animal milk products will be explicitly stated on the packaging by the manufacturer.

Where can I find lactose free products?

Much lactose-free milk and alternative milk products can be found at larger supermarkets and can also be sourced online. Some manufacturers are Lactofree (Arla), Candia, supermarket home brands, free from milk (Alpro, Oately, Rice Dream, Good Hemp, Koko and Provamil.) Please note rice milk should not be given to children under 4 ½ years of age.

Other products, due to the processing methods used, might be lower in lactose naturally and some people can eat them with no problem such as standard hard cheeses and some yoghurts. Many other foods are typically free of lactose.

The new ‘alternative’ on the block:

Tiger nut milk is a new marketed product trend, and I really don’t see the point of having this milk, unless you are from Spain and have Horchata as a cultural drink. Tiger nuts are tubers, and you can buy tiger nut milk ready made – but often making your own is advocated by bloggers and companies alike. Marketed as paleo – with little other nutritional content in the milk except for carbohydrate this marketing ploy seems a bit odd. Neither has it been tested for fodmap content.

So, people who have food intolerances and IBS, or those with inflammatory bowel disease, who may have associated conditions that result in extreme lethargy are required to make their own milk? You have to be kidding, right? There is no advantage to having this product nutritionally over and above other milk, and it does not naturally contain reasonable levels of calcium. This is exploitative of vulnerable patients in my opinion and risks long-term low calcium intake.

Is animal milk bad for me?

No, quite the opposite in fact – lactose-free animal milk contain good levels of calcium iodine and vitamin B12. Unless you have any religious, cultural or ethical reasons to avoid it, you could just swap to lactose-free animal milk products. These products contain the same level of nutrition found in regular animal milk and have the added advantage of tasting the same. We also know that the calcium found in animal milk is slightly more readily absorbed into the body than the calcium used to fortify plant-based milk.

The internet is full of alternative articles scaremongering around the consumption of cows milk. While I have no issues at all with people who decide to avoid animal products for ethical, cultural or religious reasons, scaremongering others to avoid cows milk due to spurious health risks and unevidenced harms is unacceptable.

You might have heard that animal milk leaches calcium from the bones, this is just untrue, and stories of milk being ‘too acidic’ for the body has no basis in science. Neither does milk cause excessive mucus production in the body or inflammatory bowel disease.

However, if you have changed to plant-based milk for religious, ethical, cultural or personal choice, do ensure these are fortified with calcium and ideally vitamin D (plus vitamin B12 if you are vegan.)

Another nutritional consideration for those avoiding animal milk is that milk and dairy products are the primary sources of iodine for most people. So, avoiding cows milk and/or fish can also risk low levels of iodine in the body. Adults need 150 micrograms per day, pregnant and nursing mothers slightly higher at 200 micrograms, most milk alternatives are rarely fortified, too much-added iodine can also be problematic so ask your dietitian if you feel you are not getting adequate amounts.

What about raw milk?

Raw milk contains lactose and is therefore unsuitable for people with lactose intolerance and can risk gastroenteritis (food poisoning) if it is not properly treated. I would not take the risk of drinking raw milk, particularly if you have any other digestive complaints.

Can I buy a supplement to help me digest lactose?

Yes, they are available online or from health food shops. However, the effectiveness of them varies. But they might be useful to have to hand when eating out and travelling when it might be a little more challenging to avoid lactose.

Does having lactose intolerance affect my future health?

Not generally, but not getting adequate calcium in your diet because you have stopped having all milk products long term can lead to weakened bones. Adults should ensure they have at least three portions of lactose-free dairy or calcium-fortified alternatives a day (a portion size is a glass of lactose-free milk, a small matchbox size of hard cheese, or a yoghurt.) People with bowel diseases and teenage boys need more than this, and other children less. Discuss with your doctor or dietitian. A useful calcium information sheet can be downloaded free from the British Dietetic Association website under ‘food facts’.

I do not have any affiliations with the dairy industry and have never been funded or paid by them.