According to Allergy New Zealand, lactose intolerance is one of the most common food intolerances.
Lactose intolerance is medically defined as when a person’s body doesn’t produce enough of the lactase enzyme to break down the lactose sugars found in dairy milk.
However, lactose intolerance is not black and white, as it can be caused by different digestive illnesses or abdominal injuries. People can become lactose intolerant if their DNA does not create lactase, but their gut produces some; or if their digestive system creates lactase but still fails to completely digest lactose-containing foods.
Humans are designed to be lactose tolerant at birth because breastmilk, like cow’s milk, contains lactose. However, most adults become less tolerant as they age.
Lactose intolerant people usually notice symptoms appearing within 30 minutes to 2 hours after consuming food or drink that contains lactose (Mayo Clinic):
Stomach and digestive tract complaints such as abdominal cramps, bloating, gas, diarrhoea, nausea / vomiting, irritable bowel, colitis.
Nutrient deficiencies such as anaemia, osteoporosis.
Breathing difficulty, chronic cough, asthma, sinusitis, bronchitis.
Skin conditions such as eczema or psoriasis.
Muscle and bone disorders such as stiff joints, arthritis, gout.
Other allergic reactions, frequent infections.
Fertility issues such as impotence, inability to conceive, miscarriage.
Nervous system issues such as chronic headache, memory problems, irritability, depression, or other mood issues.
Cow’s milk can also potentially cause a few other problems for humans who aren’t lactose intolerant but have other health issues. It has proteins and hormones that can affect your skin’s complexion, can be relatively high in calories, and is insulinogenic (meaning diabetics must tread carefully).
Intolerances: They’re a real thing
Allergy New Zealand identifies the following common culprits in food intolerance:
- Lactose intolerance, a condition in which a person cannot digest the sugar found in dairy products, is one of the most common food intolerances.
A sensitivity to naturally occurring food chemicals can cause symptoms of intolerance. These chemicals include:
Natural preservatives found in a wide variety of fruits, vegetables, nuts and spices
produced during fermentation, aging and ripening
an amino acid found naturally in all protein foods.
- A specific type of intolerance can develop to the protein in wheat and other grains called gluten. This condition is called Coeliac disease, and it is estimated that 1 in 300 New Zealanders are affected.
Recognising the difference between allergies and intolerances can be confusing, but studies have shown that food intolerances are a real condition and deserve to be taken seriously.
One study in the medical journal Allergy (2008) showed that 34% of parents reported food allergies in their children, but 29% of those cases were actually food intolerances masquerading as allergic reactions.
A British study by the NHS Foundation Trust shows that while only 0.8% of British adults had diagnosed coeliac disease, a further 12% of British adults report symptoms when they eat gluten-containing foods and their systems prove it is a real intolerance. These patients show visible reactions to gluten when their gut tissue is viewed under a microscope.
Causes of lactose intolerance
There are many different causes of lactose intolerance. The main one is surprising – it’s your genetics.
Certain areas in the world have many more adults who can tolerate lactose, because their people descended from traditional cow herders who relied on their cows for nutrition. For example, nearly 99% of Swedish and Dutch people are tolerant of lactose, but regions with less cow milk in their history show more intolerance. Our high proportion of lactose tolerance in New Zealand points to our heritage as cattle farming colonialists.
Other common causes of lactose intolerance include:
- Gastroenteritis, gut illnesses, or gut irritation
- Injury to the gut or surgery to the gut
- Irritable bowel syndrome
- Repeated courses of antibiotics causing gut irritation
How to know if you are lactose intolerant or sensitive
Have your GP conduct the proper medical tests
The first step is to get a simple blood test for lactose intolerance from your GP, and talk with your doctor about other possible causes for your symptoms, such as IBS.
Don’t make the mistake of assuming you’re lactose intolerant and immediately cutting out all dairy products from your diet. This can cause nutritional deficiencies that can irritate your gut even more.
Sadly, recent surveys by Allergy UK show that nearly half (44%) of those who say they are lactose intolerant have not been diagnosed by a doctor, but have relied on online information about symptoms. 72% of these self-diagnosers had removed all dairy from their diet, even foods that don’t contain much lactose.
Some have even turned to bogus and often hilarious non-medical tests. Tennis player Novak Djokovic reports using the applied kinesiology test, where the person holds a certain food in their hand while the tester searches for signs of muscle weakness. Just to be clear, the American College of Allergy, Asthma and Immunology has declared there is “no evidence of diagnostic validity” for this test. (Try holding a watermelon and taking the test – it will undoubtedly “prove” that you are intolerant or allergic to watermelons.)
Alternative sources of calcium and other nutrients
There are lots of alternatives to milk and dairy products these days. You should speak with your GP if you frequently have symptoms of lactose intolerance after eating dairy foods, and ask about alternative ways for you to get enough calcium while cutting back on dairy milk.
Many lactose intolerant and gluten intolerant patients can also be treated with the FODMAP diet developed for IBS patients by Peter Gibson of the Alfred Hospital and Monash University, Melbourne. The FODMAP diet restricts foods that contain Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. These fermentable sugars generate extra gas bacteria, resulting in the common IBS and intolerance symptoms.
Reintroduce it gradually over time
Some of the many causes of lactose intolerance are temporary, such as an injury or illness in the gut, meaning lactose intolerance itself can often be temporary. Doctors report patients “growing out of” or “growing into” lactose intolerance as sensitivity in the gut increases or decreases.
For this reason, it is important to try to reintroduce lactose-containing foods gradually over time.
You can even try different brands of milk to see which ones treat your digestive system the most kindly. Canstar Blue researches and rates customer satisfaction with long life milk on their website.
Continue to breastfeed lactose intolerant babies
Mothers with lactose intolerant babies are medically encouraged to continue breastfeeding, because breastmilk helps the root cause, the gut irritation, to heal. Breastmilk also contains essential immunities that can only be passed from mother to child, and which a milk formula cannot replicate.
Since gut irritation is often temporary, a baby can often grow out of their lactose intolerance while still in the breastfeeding season.