In Defense Of Milk (Part 2)

In Defense Of Milk (Part 2)

I’m often asked about milk and dairy products – what I think about them, if they’re safe, if they should really be included in the Dietary Guidelines, and if non-dairy alternatives are healthier or more sustainable than conventional dairy products. This is the second article of a two-part series on milk. The first article focused on milk quality and safety. This article will address the current recommendations and nutritional benefits of milk.

 

Current Recommendations

The Dietary Guidelines for Americans (DGA) were recently reviewed and updated. This process includes hundreds of experts and scientists who systematically review the best research and scientific evidence regarding diet and health. The 2015 Dietary Guidelines still recommend that adolescents and healthy adults consume three 1-cup servings of dairy per day and they affirm the vital contribution made by milk, yogurt, and cheese (1, 2). 

This new set of Dietary Guidelines introduces three different healthy eating patterns or styles: 1) Healthy U.S. Style, 2) Healthy Vegetarian Style, and 3) Healthy Mediterranean Style. Dairy is part of all three healthy eating styles and is still recognized as one of the five major food groups. It includes fluid milks, cheeses, yogurt, and other foods that contain these dairy products. Plant-based non-dairy alternatives like almond milk and rice milk are not included in the current Dietary Guidelines (soymilk that is fortified with calcium, vitamin A, and vitamin D is an exception). While the DGA Committee acknowledges that these substitutes are typically a source of calcium, they are not comparable enough to cow’s milk in terms of other nutrients to be included in the Dairy Food Group (2, 3).

 

Nutritional Benefits

The Dairy Group was initially established as part of the Dietary Guidelines because dairy products are the primary source of calcium in the American diet. In fact, food supply data from 2010 indicates that most of the calcium that is consumed by Americans (72%) comes from milk and milk products (2). Milk, yogurt, and cheese are also a source of 8 other essential nutrients – protein, potassium, phosphorus, vitamin D, vitamin B12, vitamin A, vitamin B2 (riboflavin), and vitamin B3 (niacin). One cup of cow’s milk provides at least 10% of the recommended Daily Value for each of these nine essential nutrients. Milk is considered to be the number one source of all nine nutrients for children (4, 5) and is also the number one source of six of these nine nutrients for adults (1, 5). 

Compared to cheese, fluid milk and yogurt contain less saturated fat and sodium and more potassium, vitamin A, and vitamin D (2, 3). The percentage of fat in whole milk is lower than most people realize – about 3.5%. Fat-free (skim) and low-fat (1%) dairy products provide the same nutrients but less fat and fewer calories than higher fat options like reduced-fat (2%) and full fat (whole) dairy products (5). 

Calcium, vitamin D, and potassium are nutrients of particular concern because so many Americans struggle to meet the daily recommendations (1, 2, 3). It is estimated that 42% of individuals in the United States (> 1 year of age) don’t even reach the halfway mark for their daily calcium needs and 94% have intakes below the halfway mark for vitamin D (2). 

There is strong evidence that demonstrates that consumption of milk and dairy products is associated with better bone health (especially children and adolescents), lower blood pressure in adults, and a reduced risk of cardiovascular disease.  Moderate evidence also suggests a reduced risk of type 2 diabetes, a reduced risk of certain types of cancers, and a reduced risk of obesity (2-6).

Fat in Dairy Products

Although we tend to think of the fat in dairy products as saturated fat only, there is actually quite a variety of fatty acids in dairy products (5). Dairy fat is made up of more than 400 different types of fatty acids – two-thirds of which are saturated fats. The remaining third are mostly mono- and polyunsaturated fatty acids (5). 

Since 2009, there has been considerable research on fat in dairy products that is both interesting and compelling (3, 5, 6). So far, the evidence seems to indicate that individuals who consume full-fat or reduced-fat dairy products (i.e. whole milk or 2% milk) are no more likely to develop cardiovascular disease or type 2 diabetes compared to individuals who consume only low-fat or non-fat dairy (1% or skim milk) and, in some cases, may actually be at lower risk for these chronic diseases (5, 6). Some studies also suggest that consumption of dairy foods (including full-fat varieties) may decrease the likelihood of weight gain (6). 

A controlled clinical trial (published in 2015) explored the role of full-fat dairy foods in a modified DASH diet (5). DASH is an acronym for “Dietary Approaches to Stop Hypertension”. The traditional DASH diet emphasizes the inclusion of fresh fruits, vegetables, and low-fat dairy products because these foods are good sources of potassium, magnesium, and calcium (anti-hypertensive nutrients). The results of the modified DASH diet study that included higher fat dairy foods had the same effect on lowering blood pressure. It also reduced blood levels of triglyceride and did not increase LDL (“bad”) cholesterol (5). 

All of these findings certainly challenge the existing recommendations that encourage consumption of low-fat and non-fat dairy sources instead of full-fat varieties. Still, this research is relatively new and mostly based on observational studies so far. More randomized controlled trials are needed to better understand these associations (5). For now, the new 2015 Dietary Guidelines and other national health organizations still recommend low- and non-fat dairy products and encourage a healthy eating pattern (3, 5, 6). They do, however, seem to be softening their stance on fat (5, 6). The bottom line is that dairy products definitely contribute to a healthy diet and come in a variety of options. Are you getting your 3-a-day?

 

Sources

  1. Developing the Dietary Guidelines for Americans.  Available at http://health.gov/dietaryguidelines/2015/guidelines/introduction/developing-the-dietary-guidelines-for-americans/.
  2. Scientific Report of the 2015 Dietary Guidelines Advisory Committee, Available at https://health.gov/dietaryguidelines/2015-scientific-report/15-appendix-E3/e3-6.asp.
  3. Chapter 1 – Key Elements of Healthy Eating Patterns.  Available at https://health.gov/dietaryguidelines/2015/guidelines/chapter-1/a-closer-look-inside-healthy-eating-patterns/.
  4. Dairy Council of California.  Milk by the Numbers.  Available at http://www.healthyeating.org/Portals/0/Documents/Milk%20Dairy/Milk_program_2012.pdf.
  5. National Dairy Council.  Available at https://www.nationaldairycouncil.org/
  6. TIME Magazine.  Why Full-Fat Dairy May Be Healthier than Low-Fat.  Available at http://time.com/3734033/whole-milk-dairy-fat/.


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