Dairy: Are you unnecessarily overlooking the benefits?
It almost seems fashionable now to remove dairy from our diet doesn’t it? Some individuals are reaching for the almond and coconut milk, based upon the perception that this is the ‘healthier alternative’. However, could they be missing out on the potential benefits to health that dairy products provide? Let’s take a deeper look as we refer to the scientific research to see what dairy brings to the table …
Lactose Intolerance: What Is It?
Dairy products such as cheese, milk and yogurt, contain the sugar lactose (disaccharide). Lactose is broken down into smaller sugars glucose and galactose (monosaccharides) by the enzyme lactase within the small intestine. However, following the first few months of human life the activity of lactase decreases within some individuals resulting in ‘lactase non-persistence’ (1). Undigested lactose within the small intestine is then fermented by bacteria within the colon, leading to the production of gas (methane, hydrogen and carbon dioxide) and the commonly cited symptoms of bloating, flatulence or abdominal pain (2). Furthermore, an increased intestinal osmotic load (increase in intestinal water) may occur which can lead to diarrhoea (2).
The implementation of a FODMAP (Fermentable Oligosaccharide Disaccharide Monosaccharide and Polyols) Diet by clinical professionals is increasing utilised to treat individuals with IBS (Irritable Bowel Syndrome) (3). Due to the fermentation of short chain carbohydrates within the gut causing gastro-intestinal complaints a withdrawal of lactose intake may be incorporated (3).
It is important to consult an accredited medical professional (e.g. dietitian or doctor) with regards to lactose intolerance diagnosis/treatment.
Should we all be avoiding lactose?
Although ‘lactase non-persistence’ is typically observed following the first few months of life, ‘lactase persistence’ has been found within individuals. This is thought to be related to the domestication of cattle and increased production/consumption of dairy leading to a regulatory genetic mutation as humans evolved (1). To quote (2) “Up to 70% of the world population has lactase non-persistence, but not all are intolerant to lactose as many nutritional and genetic factors influence tolerance … Ethnic origin affects the frequency of lactose intolerance. In adults, white North Europeans, North Americans and Australians have the lowest rates ranging from 5% in British population to 17% in Finland and Northern France.”
Although, lactose restriction is a common treatment for diagnosed lactose intolerance, individuals may tolerate lactose amounts of up to 12g without any adverse side effects, especially if spread throughout the day (4). Furthermore, fermented dairy sources are an alternative due to the lower lactose content e.g. cheese, whilst live cultures (bacteria) present within yogurt aid lactase activity and lactose digestion (5).
Dairy and acid-alkaline balance
It is claimed that dairy consumption increases dietary acid load due to its protein and phosphorus content, which is therefore compromises bone health as a result of increased urinary calcium loss (6). However, urine calcium does not reflect whole body calcium status (6). Although the pH of urine can be altered by dietary intake, this is not true for blood pH, which is tightly regulated between a pH of 7.35-7.45 (7). Different parts of the body are of varying pH ranges due to their specific functions during the digestive process, as the stomach has a pH of 1-2.5 whereas the small intestine a pH of 6.6-7.5 (8).
Raw or non-dairy: The alternatives?
It has been suggested that the pasteurisation process (heating of milk to ensure pathogens are destroyed) significantly decreases the nutritional value of milk. However, pasteurisation has been shown to not result in a significant change in protein quality or other nutrient contents (9). Furthermore, as raw milk does not undergo the pasteurisation process, there could potentially be an increased risk of pathogen contamination (10).
Non-dairy based alternative milks are becoming ever increasing popular. When now scrolling through social media or browsing a magazine article you will typically find the promotion or inclusion of such choices e.g. almond or coconut milk. However, how do non-dairy milk options compare to dairy sources? The below infographic highlights the differences in kcals and macronutrient (protein, carbohydrate, fat) content.
If you are diagnosed as lactose intolerant by a clinical dietitian or doctor, or simply do not feel that you handle dairy well, then non-dairy sources shall obviously be an alternative. It is clear to see within the table above that dairy based milk options are a much greater source of protein than all non-dairy alternatives (apart from soya milk). Furthermore, skimmed and semi-skimmed options are of similar kcals content compared to some non-dairy options. Both almond (unsweetened) and coconut (original) milk contain fewer kcals than their dairy counterparts, which makes them a popular choice amongst dieting individuals. As dairy protein provides numerous benefits that would be beneficial for individuals pursuing body composition orientated goals, which shall be expanded upon in the next section, it is important to not overlook their contribution when deciding upon dietary options. For individuals that do opt for non-dairy milk sources out of personal preference then integrating other dairy sources such as yogurt (e.g. Greek yogurt) and some cheeses will ensure the benefits of dairy are not overlooked.
What are the potential benefits of dairy consumption?
A reason often cited by individuals for the withdrawal of dairy from their diet is due to a potential inflammatory effect. Inflammation has been shown to contribute and develop such chronic diseases as cardiovascular disease, diabetes and metabolic syndrome (11). However, no adverse effects on low-grade systemic inflammatory biomarkers were found in overweight and obese adults who consumed dairy products (11). Furthermore, a review of clinical evidence found an anti-inflammatory effect for both healthy individuals and individuals with metabolic disorders (12).
Dairy products are considered one of the best dietary calcium sources due to their rich calcium content, high bioavailability and relatively low cost (13). Calcium and phosphorus play an integral role within bone health (14), whilst additional roles of calcium include: muscle contraction, nerve conduction and blood clotting (15).
High quality protein
Milk protein consists of 80% casein (slower digestion/absorption) and 20% whey (faster digestion/absorption) protein. Both casein and whey are high quality protein sources due to their rich essential amino acid, particularly the branch chain amino acids (BCAA) leucine, isoleucine and valine (13). This highlights the effective role dairy products can play in stimulating muscle protein synthesis, which can assist the maintenance or development of muscle.
The consumption of milk can contribute to daily fluid intake. Furthermore, such consumption can aid fluid retention due to the electrolyte content therefore assisting the maintenance of a hydrated state (18).
For individuals that participate in regular exercise or sporting activities the consumption of milk has been found to assist with supporting the recovery process incorporating the 3 R’s: Repair, Replenish & Rehydrate (19). The high quality protein provided by milk consumption aids with the repair of exercise induced muscle damage. The carbohydrate content of milk (including flavoured milk e.g chocolate milk) plays a role within glycogen (carbohydrate energy stores) replenishment. When sub-optimal carbohydrate is ingested the protein content of milk can assist glycogen replenishment. Finally, due to the fluid and electrolyte content of milk this therefore contributes to the rehydration process.
When on an energy restricted diet a higher calcium intake (e.g. dairy consumption) suppresses the activity of calcitrophic hormones aiding the repartitioning of energy via increased lipolysis and thermogenesis (16). A reduced efficiency of fat absorption has been found when calcium binds with fatty acids leading to the production of calcium soaps that increase faecal fat excretion resulting in energy loss (17).
Due to dairy’s high protein content (casein and whey) ingestion of such food sources can aid satiety (the feeling of fullness) which can therefore influence a potential reduction in total energy intake (13).
The presence of ‘good bacteria’ within yoghurt aids lactase activity, which we read earlier plays a role within the digestion of lactose (5), whilst antimicrobial properties are also present within milk (9). The consumption of ‘good bacteria’ is beneficial for gastro-intestinal and immune health (9).
- Although numerous individuals may display lactase non-persistence, not all are intolerant to lactose as many nutritional and genetic factors influence tolerance.
- Lactose restriction is a common treatment for diagnosed lactose intolerance, with some individuals potentially able to tolerate lactose amounts of up to 12g without any adverse side effects, especially if spread throughout the day.
- Dairy provides numerous benefits including: a high quality calcium, protein and beneficial bacteria source, aiding hydration and exercise recovery, assisting satiety, anti-inflammation and weight management.
- Consult a dietitian or doctor with regards to the diagnosis and treatment of lactose intolerance.
This article is an overview of the current literature upon dairy and is not to be taken as medial advice or change any advice received from a medical professional. Individuals must consult a dietitian or doctor regarding the diagnosis or treatment of lactose intolerance, including if contemplating making any changes to current dietary intake.