Recommendations to eliminate dairy are often followed by a plethora of “what about” questions from patients. What about goat milk? What about sheep cheese? What about A2 milk?
There is something about dairy that we all love and which makes it one of the most challenging dietary categories to abandon, despite the negative health consequences. Giving up the glass of milk seems to be an easy first step, but once we consider cheese and yogurt, attitudes start to change.
Most health professionals are aware of the many reasons to eliminate dairy. The issues of quality and the presence of hormones and antibiotics are almost universally agreed upon, but easily solved by using organic dairy from pastured cattle. Even then, the dairy is problematic for many. Lactose intolerance affects nearly 65 percent of the human population, but the raw milk industry would argue they found the solution to this problem. Neither milk sugar nor the quality of milk are the greatest health concerns with this food group. Our chief concern is inflammation.
Insulin-like Growth Factor (IGF-1)
Systemic inflammation is quickly becoming a root cause of many chronic diseases of Western societies, including coronary heart disease, diabetes mellitus, cancer, hypertension, obesity, dementia, and allergic diseases. Dairy is recognized as a known trigger of inflammation because it raises insulin-like growth factor-1(IGF-1) as it shifts the hormonal axis of insulin, growth hormone, and IGF-1. IGF-1 induces cell proliferation, stimulates the adrenals and gonads, and is involved in the pathogenesis of acne, atherosclerosis, diabetes mellitus, obesity, cancer and neurodegenerative diseases. As dairy increases IGF-1, it can become an instigator of our most common health conditions, calling for its elimination.
A1 and A2 Sub-variants of Beta-casein
Various forms of casein, the predominant protein in milk, have presented another set of health problems and been the focus of recent debates regarding dairy consumption. Most species’ milk contains 3 or 4 types of casein. One type – beta-casein – exists in at least 12 different sub-variants, including the A1 and A2 sub-variant that receives so much attention today.
Beta-casomorphin-7 (BCM-7)
The A1 sub-variant of casein is found in common cattle breeds. As it is digested by proteolytic enzymes, it yields a bioactive peptide known as bovine beta-casomorphin-7 (BCM-7). This peptide has been targeted as the agent responsible for the gastrointestinal complications often noted with dairy consumption. It has been shown to bind to μ-opioid receptors in the gastrointestinal tract and delay transit time, increase mucin production to a degree that interferes with commensal bacteria, and alters lymphocyte proliferation. Changes in commensal bacteria have been identified in other studies by a notable decrease in the amount of short-chain fatty acids produced by normal microbiota fermentation. (5) BCM-7 has also been shown to increase inflammatory markers and immunoglobulins, enhance leukocyte infiltration into intestinal villi, and increase the expression of Toll-like receptors in the gut, all of which are proinflammatory activities. Opioid receptors exist in the nervous, endocrine, and immune systems, too. As BCM-7 affects these other organ systems, risk factors for various chronic health conditions rise. Finally, BCM-7 is considered an oxidant of LDL cholesterol – a major risk factor for coronary artery disease and arteriosclerosis.
Most milk contains a mixture of the A1 and A2 sub-variants of beta-casein; however, the A1 sub-variant is favored in the dairy of most cattle breeds. Milk strictly containing the A2 sub-variant is rare and only sourced from carefully selected cattle breeds. The presence of BCM-7 in milk exclusively containing the A2 variant is minimal or lacking. Therefore, many argue that “A2 milk” does not promote inflammation or the gastrointestinal complications that accompany “A1 milk.” This phenomenon has been confirmed by studies which show a mitigation of the negative health effects associated with consumption of A1 milk after consuming A2 milk.
Goat/Sheep Milk
Although bovine forms of strictly A2 sub-variant milk are uncommon, goat and sheep milk contain the A2 sub-variant and are more readily accessible. The lack of the inflammatory A1 sub-variant partially explains why many consumers tolerate goat/sheep milk better than bovine milk. However, there is another distinguishing feature of this species’ milk. The beta-casein content is far greater than in bovine milk, which is dominated by the proinflammatory alpha-casein. Despite these differences, cross-reactivity is very high between all three species, leading to the necessity for complete dairy elimination in many individuals.
As the arguments swirl around the varieties and componentry of dairy, we must not forget our ultimate goal – optimal health. If all forms of dairy have the capacity to induce inflammatory processes that may hinder healing at best and initiate chronic disease processes at worst, then it is important to educate consumers on the importance of complete elimination. As practitioners, it is important (and challenging at times) to identify individuals who may safely consume some forms of dairy and those who should abstain from all dairy.
