The pros and cons of dairy

Discussing dairy can be controversial as there are so many conflicting views.  Some feel that it should definitely be included in the diet, others think that it is fine to have it in moderation and lastly those who consider that we should not consume it at all. Dairy includes milk and any other products made from milk, including cheese, butter, yogurt, etc. In this article I discuss some of the pros and cons of having dairy.

What we eat is initially influenced by where we are born, live, our culture and taste buds.  If you were born and grew up in Africa or Asia your diet will be very different to having grown up in North America or Europe.  It’s affected by what is easily available and affordable, the climate, lifestyle, etc. Our food not only provides us with energy, but also the nutrients that we need. Some foods however may be detrimental to our health, as discussed below.  What I intend to do in this article is provide you the facts and let you decide whether to include it, exclude it or how much to have.

Food for babies

Milk is what all mammals produce and provide to their young.  Humans though are the exception as we continue to have dairy beyond the weaning stage, when a child is introduced to solid foods, as we consume milk from another mammal as adults.  We get accustomed to dairy, enjoy its taste and for some of us it is our favorite comfort food.  In addition dietary guidelines set by health authorities worldwide recommend that dairy be included daily.

Did you know that the composition of milk varies depending on which mammal it comes from? This is because each young mammal needs different proportions of nutrients to grow and develop. Listed below are the nutrients from human milk and from whole cows milk.  As seen below cows milk is over 3 times higher in protein than human milk and has less fat than human milk. What’s most striking is that it has about 4 times the calcium of human milk, which is because calves need more calcium to grow rapidly in size.

Source: USDA Food Content

Calcium

Calcium is required for many functions in the body, including is essential for healthy bones and teeth and also to support nerve and muscle functions.  The recommended daily calcium requirements vary depending on where you live.  For adults in the UK it is 700 mg [1] and in the USA it is 1,000 mg a day [2] whereas in Japan is between 550 mg and 800 mg a day [3].  Our dietary guidelines recommend that we include dairy products as they are a good source of both protein and calcium.

However, there are research studies that differ with this view that including dairy results in strong bones. For instance in a Harvard study it was found that greater milk consumption during teenage years did not translate into a lower risk of hip fracture in older adults [4]. Interestingly a study was done in Ho Chi Minh City where the bone mineral density of 105 Mahayana Buddhist nuns who were vegans was compared to 105 omnivorous women.  This showed that although the nuns who were vegans had dietary calcium and protein which was lower than the omnivores, it did not have an adverse effect on their bone mineral density[5].

As seen below dairy is a good source of calcium, but there are also other foods that are high in calcium.

Source:  www.nal.usda.gov/fnic/foodcomp/search/

Lactose Intolerant

Lactase is the enzyme needed to digest and absorb lactose, the sugar found in milk.  This enzyme is present in most of us when we are born, allowing us to digest milk that is our main source of food at this stage in our life.  However as we grow some of us, depending on our heritage, will no longer be able to digest milk as the lactase enzymes decrease.  Asians, South Americans and Africans tend to be lactose intolerant.  Those originating from Europe and North America have adapted to eating dairy, although there is a smaller percentage from these regions that are also lactose intolerant.

Symptoms of digestive discomfort are experienced when those who are lactose intolerant consume dairy.  These include gas, bloating, cramps or diarrhea and the severity of the symptoms varies, for some it is mild and for others it could be severe. Also, may find that some can have small portions of hard cheese or kefir as these contain less lactose. The food industry has of course provided for this growing market in lactose intolerant consumers by creating lactose free dairy products, which effectively is the lactase enzyme being added to milk, yogurt, etc to break down the lactose and make it lactose free so there are no symptoms experienced.

High in hormones

All dairy cows have recently given birth to their young and naturally their hormone levels are high. There are many differing views on how much of these hormones are passed on and absorbed when we consume dairy.

Recombinant Bovine Growth Hormone (rBGH) or Recombinant Bovine Somatotropin (rBST) is an artificially produced hormone given to cows to increase their milk production.  This is permitted in the United States of American but not in the European Union, Canada and other countries.  As the cows are milked so frequently they often develop mastitis and need to be put on antibiotics, which does promote the development of antibiotic resistant bacteria and the extent of this being transmitted to humans is unclear.

Insulin like Growth Factor 1 (IgF-1) is a hormone that plays an important role during childhood, it peaks during puberty and we have lower levels of this as adults.  There are positive associations between some cancers and high IgF-1 levels.  Evidence suggests that having milk may increase circulating IgF-1 levels [6] and there is further evidence that having milk from a cow given rBGH will result in higher IgF-1 levels[7].

Milk is also linked to causing teenage acne possibly because of the presence of hormones.[8][9]

Tastes good

One of the main reasons we continue with dairy beyond childhood is because we enjoy it’s taste; milk, yogurt and ice-cream are creamy. Dairy also has a higher satiety factor, keeping us full for longer as it contains fat and protein, which means we don’t feel hungry soon after consuming it.

For others it is a food they have had culturally for generations and is now part of their diet.  For instance we are accustomed to having milk with our breakfast cereal or in tea/coffee, cheese as a topping on our pizza and yogurt as a snack.  Also, yogurt or kefir is a staple part of the diet in some parts of the world because it is a good source of beneficial bacteria that supports a healthy digestive system.

However, some dairy products are far from its natural state.  The refrigerated aisles in supermarkets are stocked with a range of dairy products, many of which contain sugar, artificial sweeteners or preservatives.  It is best to always read the labels to check what has been added to these packaged foods like flavored milks, fruit yogurts or processed cheese.  They may be easy snack options to have on the go but they are not the healthiest option.  Often it is better to make your own fruit yogurt by adding fruit to natural yogurt, as it will be lower in sugar rather than buying a fruit yogurt.

What’s the best source

When having dairy it is best to know what the source is.  We may have idyllic images of cows in green pastures but this is often far from reality.  Many farms have cows that are confined in barns and have limited access to a pasture.  They are fed grains that may have been sprayed.  Also as cows are more susceptible to infections living in these conditions and being milked so frequently, they may be given antibiotics.

Organic is best to avoid having any milk from cows given additional hormones or antibiotics or pastures that have artificial and chemical fertilizers used on them. All organic farms must be registered with an organic control body and meet specific standards based on guidelines set.  In the UK these are implemented by the Department for Environment, Food and Rural Affairs (Defra).  It takes a minimum of 2 years to convert the land to organic status.  All feedstuff must be certified to organic standards and maximum use should be made of grazing.  Artificial fertilizers are not permitted in organic farms.  Also, veterinary medicines and antibiotics must not be used as a preventative medicine but should be used to prevent distress in the event of illness or injury.  There are also standards set for the amount of housing space required for dairy cows so that they do not live in cramped conditions.[10]

Conclusion

As seen there are many differing views on whether to have dairy. There are also many choices when having dairy, should we have full fat, semi-skimmed or low fat.  We then need to weigh out the benefits of organic versus its higher cost.

Some will have strong views on including it in their diet and others have views on excluding it from their diet, but most people will be somewhere in between these views and find the balance that suits them.

This article first appeared in Good Zing 

References

[1] British Nutrition Foundation. Nutrient requirements. Revised Oct 2016

[2] National Institute of Health. Dietary Reference Intakes (DRIs): Recommended Dietary Allowances and Adequate Intakes, Elements.  Food and Nutrition Board, Institute of Medicine, National Academies

[3] Ministry of Health, Labour and Wellness. Overview of Dietary Reference Intakes for Japanese (2015) Estimated average requirements and recommended daily requirements. Estimated Average Requirement and Recommended Dietary Allowance. Page 32

[4] Diane Feskanich, Heike A Bischoff-Ferrari, Lindsay Frazier and Walter C Willett. Milk Consumption During Teenage Years and Risk of Hip Fractures in Older Adults. JAMA Pediatr. 2014 Jan; 168(1): 54–60.

[5] Ho-Pham LT, Nguyen PL, Le TT, Doan TA, Tran NT, Le TA, Nguyen TV. Veganism, bone mineral density, and body composition: a study in Buddhist nuns. Osteoporos Int. 2009 Dec;20(12):2087-93. doi: 10.1007/s00198-009-0916-z. Epub 2009 Apr 7.

[6] Qin LQ, He K, Xu JY. Milk consumption and circulating insulin-like growth factor-I level: a systematic literature review. Int J Food Sci Nutr. 2009;60 Suppl 7:330-40. doi: 10.1080/09637480903150114. Epub 2009 Sep 9.

[7] Epstein SS Unlabeled milk from cows treated with biosynthetic growth hormones: a case of regulatory abdication. Int J Health Serv. 1996;26(1):173-85.

[8] F William (Bill) Danby Acne, dairy and cancer Dermatoendocrinol. 2009 Jan-Feb; 1(1): 12–16

[9] Adebamowo CA¹, Spiegelman D, Danby FW, Frazier AL, Willett WC, Holmes MD. High school dietary dairy intake and teenage acne. J Am Acad Dermatol. 2005 Feb;52(2):207-14.

[10] Department for Agriculture, Environment and Rural Affairs.  Organic milk production