The dairy free diet is something that in recent times has become increasingly popular. There are several factors that have definitely helped push the dairy free diet and these include increased scrutiny on the dairy industry. People have become concerned about how our dairy is farmed and the hormones that are reported to be contained in cow’s milk and dairy products. Dairy has recently been blamed for everything from cancer to obesity, but what is the real truth behind dairy and should you really be avoiding it?
There is a proportion of the population that should most definitely avoid dairy, those who are lactose intolerant. Lactose is a sugar found in milk and relies on an enzyme called lactase to break it down efficiently for absorption into the body. If we have enough of this enzyme then there is no problem with consuming dairy in this regard. Most of us in Northern and Western Europe have evolved to have these enzymes and are just fine with consuming dairy.
In cultures that don’t have a long history of dairy farming, such as in East Asia, they have a much higher prevalence of lactose intolerance with reports of 90% of the population is some countries being intolerant to dairy, compare this to around 5% in Northern European countries.
Symptoms of lactose intolerance include severe abdominal pain and distension, diarrhoea and wind. This is also influenced not just by an absence of lactase but also the amount of lactose present in the diet. Some people can consume small amounts of lactose with no issues, whilst others may be more sensitive.
There are also some people who may actually be allergic to certain proteins found dairy, in the same way as gluten or nut allergies. These can cause an immune reaction that attacks the digestive system and this normally comes with more severe symptoms, even in the presence of only small amounts of the allergen. So aside from those who get physical symptoms associated with intolerance or allergy, is there any other reason to avoid dairy?
Well from a nutritional perspective dairy is rich in many essential nutrients that are important for general health, including calcium, protein, vitamin D, potassium and phosphorus. Dairy products are excellent sources of protein, containing all the essential amino acids, and whey protein and casein are great low calorie, high protein supplements derived from dairy that have shown to support muscle recovery, muscle growth and even help as part of a weight loss diet.
The concerns with dairy products are often focused around the accusation that dairy cattle either are ‘pumped full of hormones’ and/or that their natural hormones are present in milk and this can have a huge impact on our health. In Europe we have strict regulation in terms of dairy farming, so the use of hormone injections is restricted and the use of any medication on dairy cattle is highly regulated to ensure it does not enter the food supply in significant amounts. However cow’s milk does still contain some hormones, so the real question is could this find its way into our bodies and have a potential negative impact on our health?
In order to answer this question we have to understand three things. Firstly, what hormones are present in cow’s milk, secondly can these actually be digested and absorbed into the body and finally are the amounts present of any concern when looking at the bigger picture of our own hormonal profile. The main hormones people are concerned about are growth hormones and oestrogen.
When discussing growth hormone it is important to note that structurally these are long chains of amino acids (human growth hormone is a chain of 181 amino acids). In order for these to have any impact on our body they would have to firstly enter the blood stream intact. The body can only absorb at most very small chains of amino acids, therefore these longer amino acid chains will be broken down in our digestive processes. This means that they will lose their structure, which determines a hormones function, and renders them unrecognisable and inactive within the body.
The female cow hormones found in milk, including oestrogen, do however have the potential to enter into the body. Fortunately our bodies have an excellent barrier to external hormones passing into general circulation and causing any unwanted effects… the liver. The liver metabolises external oestrogen and testosterone, this is the reason why oral oestrogen medication used in hormone replacement therapy has to be attached to various compounds to ‘survive’ this process and cause an effect. This process can be surpassed by very large quantities of these hormones, however the amounts present in milk come nowhere near to what would be required to have an impact on the body.
On a final note, when we consider the amounts of hormones in milk, it is a common misconception that this is actually responsible for the growth of calves and therefore these amounts could impact on humans. This is not actually the case.
Milk is designed to provide nutrients and energy, and the hormones present are those that are passively transferred in small amounts from blood stream to the milk. Calves actually produce many thousands of times the amount of hormones present in milk to support their growth, and we ourselves produce many thousands of times more than would be found in dairy products.
Many people who cut dairy do happen to lose weight, however as with most ‘elimination diets’ this is more to do with the restriction of foods that can be high in calories. If you consider that dairy is found in many baked goods, chocolate, butter and cheese that are highly caloric and easy to overconsume, then restricting dairy intake will also likely reduce calorie intake and cause weight loss. This is not so much the removal of dairy that directly causes weight loss; it is simply a result of restricting calorie intake without realising it.
This means that dairy products can be included as part of a balanced diet, as they provide many essential nutrients. Even for weight loss as long as we account for the calories we consume from dairy as part of our daily energy requirements, then there is going to be no issue with consuming dairy in this regard. Dairy is definitely something we should not fear for the reasons outlined in this article and should only be avoided in those who are sensitive to lactose or allergic to dairy.
References
Rizzoli, (2014) Dairy products, yogurts, and bone health. American Society for Nutrition. vol. 99: 1256-1262.
Juskevich, J.C. & Guyer, C.G. (1990) Bovine Growth Hormone: Human Food Safety Evaluation.
Grgurevic et al. (2016) Effect of dietary estrogens from bovine milk on blood hormone levels and reproductive organs in mice.
Larsson et al. (2015) Milk Consumption and Mortality from All Causes, Cardiovascular Disease, and Cancer: A Systematic Review and Meta-Analysis.
