Peer-Reviewed Research
Before making any diet change, it is important to understand how this change will affect one’s body. At Switch4Good, we value objective research and results. The studies below represent a solid body of evidence to support the dairy-free diet as a benefit to overall health and athletic performance—for all ages.
Centenarian and longevity studies
In the five recognized “Blue Zones” on Earth, i.e. places with the highest percentage of centenarians, the overwhelming dietary pattern shared by those longest-living peoples is 95% to 100% whole food plant-based. Despite their wide separation of geography, from Okinawa to Sardinia to Loma Linda, Blue Zones diets share commonalities: they are especially rich in beans, and whole grains or root vegetables. For more details see the BlueZones website, which also links to books and research articles.
Epidemiology / observation studies
From following the demographic, health, and outcomes data for large groups of people over years, WFPB diets are tied to lower risks of disease. Prominent examples include the Adventist Health Study 1 and 2 (additional summary), the Nurses’ Health Study, and The China Study. Population migration studies can be especially revealing, e.g. chronic disease risks (heart disease, cancer, Alzheimer’s) can differ by 10× or more for the same ethnic group members living in the US vs elsewhere, strongly suggesting that diet and lifestyle far outweigh genetics, as risk factors.
Clinical research and interventions
The carefully planned and closely monitored use of nutrition-based interventions to treat diseases, provides some of the strongest evidence in favor of WFPB diets. In clinical studies, particularly the “gold standard” of randomized clinical trials having a control group, WFPB diets have been repeatedly shown to reverse severe heart disease, type 2 diabetes, hypertension, high cholesterol, and obesity. This domain provides the key evidence backing “evidence-based” medicine and nutrition.
Biochemistry
A well-balanced WFPB diet is most aligned with growing knowledge of healthy biochemistry in the body, especially our need for antioxidants, phytonutrients, and fiber — only available from plant foods. Those needs are in addition to the familiar macronutrients (carbs, protein, fat) and micronutrients (vitamins, minerals). Plants-only nutrients play vital roles in our health, at all levels from molecules, to cells, to larger body systems (e.g. blood circulation, digestion, nervous system) and organs (heart, brain, gut and microbiome, etc).
Why Avoid Dairy
Cows’ Milk Allergy
Did you know that cows’ milk allergies might be more common than allergies to peanuts, shellfish, and eggs? Cows’ milk allergy mostly affects infants and children, but also up to 1 in 13 adults! (1) Further, a meta-analysis of 51 studies on the prevalence of food allergies found that up to 17% of people self-report an allergy to cows’ milk (2).
In addition to the immediate symptoms that can occur, such as wheezing, hives, vomiting, and life-threatening anaphylaxis, some symptoms can actually occur up to several days following dairy consumption, including eczema and acid reflux (3). This means people may not even realize their symptoms could be an allergic reaction to the cows’ milk they consumed days prior. Unfortunately, methods for reversing cows’ milk allergy, such as immunotherapy, have not been proven safe or effective, which is why doctors recommend avoiding dairy products entirely (4). Think you could be affected? Learn about the 4 Signs That You May Be Allergic to Dairy by Switch4Good expert, Dr. Vivian Chen.
Our tip to you: avoid all forms of dairy to manage symptoms, including milk from sheep and goats. Click here to learn about alternatives to cows’ milk.
References
1. El-Agamy, Elsayed. The challenge of cow milk protein allergy. Small Ruminant Research 2007; 68:64-72
2. Rona, Roberto J. et al. The prevalence of food allergy: A meta-analysis. Journal of Allergy and Clinical Immunology 2007; 20(3):638 – 646.
3. Fiocchi et al. World Allergy Organization (WAO) Diagnosis and Rationale for Action against Cow’s Milk Allergy (DRACMA) Guidelines. WAO Journal 2010.
4. Taniuchi S, Takahashi M, Soejima K, Hatano Y, Minami H. Immunotherapy for cow’s milk allergy. Hum Vaccin Immunother. 2017; 13(10):2443–2451.
Lactose Intolerance
How can cows’ milk be considered a health food when 65% of the world’s population is intolerant to it? Once someone who is lactose intolerant consumes cows’ milk or other lactose-containing dairy products, symptoms can occur within 30 minutes to two hours! (1) The struggle is real. These symptoms include abdominal pain, bloating, gas, nausea, and diarrhea (1). Cows’ milk is making those who are lactose intolerant sick.
According to the National Institute of Health, 65% of adults experience dairy intolerance, a generally lifelong inherited condition characterized by varying levels of difficulty digesting lactose (dairy sugar) (2). This condition is commonly referred to as lactose intolerance.
Our tip to you: completely avoid lactose by passing on the milk, cheese, butter, cream, and other dairy products. Click here to read Switch4Good expert Dr. Angie Sadeghi’s breakdown of lactose intolerance. If you think you might be lactose intolerant, take our quiz to find out!
References
1. NIH. Lactose Intolerance Statistics.
2. Swagerty et al. Lactose Intolerance. Am Fam Physician 2002; 65:1845-50,1855-6
Bone Density
Don’t be fooled by advertisements claiming that cows’ milk helps strengthen bones—the research tells a different story. A 2018 meta-analysis involving over 250,000 male and female subjects found no link between drinking cows’ milk and a reduced risk of bone fractures (1). In fact, according to a study published in the British Medical Journal, those getting the USDA “recommended” 3+ glasses per day had a whopping 60% greater hip fracture rate (2).
Yup, cows’ milk could actually make bones more brittle, not stronger. How can this be? Researchers suggest the milk sugar D-galactose promotes oxidative stress and inflammation, which are both linked to loss of muscle and bone (2). Additionally, while phosphorus is essential for calcium absorption, too much can be counter productive. Cows’ milk is so high in phosphorus that it can actually lead to calcium resorption from the bones (3).
Our tip to you: for truly strong bones eat more fruits and vegetables! The foods highest in calcium and 50% more bioavailable than the calcium in cows’ milk are almonds, kidney beans, and most dark, leafy greens (4). Diets higher in fruits and vegetables have been shown to lead to denser bones in younger and older adults (5,6).
References
1. Trajanoska Katerina, Morris John A, Oei Ling, ZhengHou-Feng, Evans David M, Kiel Douglas P et al. Assessment of the genetic and clinical determinants of fracture risk: genome wide association and mendelian randomisation study. BMJ 2018; 362:k3225
2. Michaëlsson K, Wolk A, Langenskiöld S, et al. Milk intake and risk of mortality and fractures in women and men: cohort studies. BMJ 2014; 349:g6015.
3. Mahdi, A.A., Brown, R.B. & Razzaque, M.S Osteoporosis in Populations with High Calcium Intake: Does Phosphate Toxicity Explain the Paradox? Ind J Clin Biochem. 2015; 30:365.
4. Amy Joy Lanou. Should dairy be recommended as part of a healthy vegetarian diet? Counterpoint. The American Journal of Clinical Nutrition 2009; 89(5):1638S–1642S.
5. Katherine L Tucker et al. Potassium, magnesium, and fruit and vegetable intakes are associated with greater bone mineral density in elderly men and women. The American Journal of Clinical Nutrition 1999; 69(4):727–736.
6. Susan A Lanham-New. Fruit and vegetables: the unexpected natural answer to the question of osteoporosis prevention? The American Journal of Clinical Nutrition 2006; 83(6):1254–1255
Asthma
Cows’ milk and other dairy products have been shown to increase increased mucus production in the body, which is a hallmark symptom of asthma (1). Researchers hypothesize that increased intestinal permeability, which has been associated with strenuous exercise, allows the casein protein to leak through the gut and therefore stimulate excess mucus production (2,3).
Why might this be? Asthmatics need more antioxidants to protect their vulnerable lungs, as they have far fewer antioxidants than most (4). By eating more foods that contain these antioxidants, they could reduce the chance of worsening symptoms by half! (5) Sounds so simple! But not for those who still consume dairy products. Unfortunately, there are not many antioxidants in dairy, so relying on dairy products may actually lead to worsening symptoms.
Our tip to you: try some chocolate soymilk. Chocolate soymilk from Trader Joe’s contains almost double the antioxidant content of store brand chocolate cows’ milk (6). This may explain why an astounding 92% of people with asthma who cut out dairy and other animal foods for one year improved their symptoms enough to go from 4-5 medications to just 1! (7) To learn more about how to include more antioxidant rich foods into your diet click here.
References
1. Frosh A, Cruz C, Wellsted D, Stephens J. Effect of a dairy diet on nasopharyngeal mucus secretion. Laryngoscope. 2019 Jan;129(1):13-17.
2. Bartley, Jamie and Susan Read McGlashan. Does milk increase mucus production? Medical hypotheses 2010; 74(4):732-4.
3. JanssenDuijghuijsen, Lonneke M et al. The effect of endurance exercise on intestinal integrity in well-trained healthy men. Physiological reports vol. 4,20 (): e12994.
4. Lisa G. Wood et al. Airway and circulating levels of carotenoids in asthma. J Am Coll Nutr. 2005; 24(6):448-55.
5. Lisa G Wood et al. Manipulating antioxidant intake in asthma: a randomized controlled trial. The American Journal of Clinical Nutrition 2012; 96(3):534–543.
6. Carlsen MH, Halvorsen BL, Holte K, et al. The total antioxidant content of more than 3100 foods, beverages, spices, herbs and supplements used worldwide. Nutr J. 2010; 9:3
7. Lindahl O, Lindwall L, Spångberg A, Stenram A, Ockerman PA. Vegan regimen with reduced medication in the treatment of bronchial asthma. J Asthma 1985; 22(1):45-55.
Hormones
It is common knowledge that proper hydration is essential to any form of exercise, but chocolate milk is not the drink of champions. Cows’ milk, even “no hormone added,” “grass-fed,” and “locally produced,” contains 15 different sex hormones, including estrogen, progesterone and testosterone. That does not even include the other 60 natural hormones found in cows’ milk and the synthetic hormones many dairy cows are given to boost milk production. Consuming these large amount of hormones can lead to a wide array of unwanted side effects and even cancer. To learn more about the toxic effects of hormones in today’s cows’ milk from Dr. Vivian Chen, click here.
ESTROGEN
Cows’ milk and dairy products are full of estrogen hormones. These products supply 60-80% of the estrogen in our diets (1). This is due to the fact that the milk people consume is taken from pregnant cows. Modern genetically-improved dairy cows, such as the Holstein, lactate during the latter half of pregnancy, when estrogen levels are highly elevated (2). In fact, just 30-60 minutes after drinking milk, estrogen levels can increase by 26%! (2) Numerous studies have found an association between excess estrogen and increased risk of breast and prostate cancers, fatigue, and weight gain (3,4).
Our tip to you: Pomegranate juice! Pomegranates contain aromatase inhibitors like ellagetanins which inhibit estrogen production (5). It is also a great anti-inflammatory food. Compared to drinking a placebo, pomegranate juice can increase Olympic weightlifting performance by 8%, decrease how hard training felt by 4%, and decrease muscle soreness by 13%! (6) And don’t be afraid of soy. Soy actually contains phytoestrogens which act as estrogen blockers (7).
References →
1. Malekinejad H, Rezabakhsh A. Hormones in Dairy Foods and Their Impact on Public Health – A Narrative Review Article. Iran J Public Health. 2015;44(6):742–758.
2. Maruyama K, Oshima T, Ohyama K. Exposure to exogenous estrogen through intake of commercial milk produced from pregnant cows. Pediatr Int. 2010 ;52(1):33-8.
3. Ganmaa D, Sato A. The possible role of female sex hormones in milk from pregnant cows in the development of breast, ovarian and corpus uteri cancers. Med Hypotheses 2005; 65(6):1028-37.
4. Ganmaa D, Wang PY, Qin LQ, Hoshi K, Sato A. Is milk responsible for male reproductive disorders? Med Hypotheses. 2001; 57(4):510-4.
5. Adams LS, Zhang Y, Seeram NP, Heber D, Chen S. Pomegranate ellagitannin-derived compounds exhibit antiproliferative and antiaromatase activity in breast cancer cells in vitro. Cancer Prev Res (Phila). 2010; 3(1):108–113.
6. Ammar A, Turki M, Chtourou H, et al. Pomegranate Supplementation Accelerates Recovery of Muscle Damage and Soreness and Inflammatory Markers after a Weightlifting Training Session. PLoS One. 2016; 11(10):e0160305.
7. Fioravanti L, Cappelletti V, Miodini P, Ronchi E, Brivio M, Di Fronzo G. Genistein in the control of breast cancer cell growth: insights into the mechanism of action in vitro. Cancer Lett. 1998; 130(1-2):143-52.
CORTISOL
We are always trying to find ways to decrease our stress levels, as stress can reap terrible effects stress can have on our minds and bodies. Stress is often controlled by a hormone known as cortisol—a stress hormone consistently found in cows’ milk (1). To make matters worse, high cortisol levels cause us to store belly fat (2) and are linked to lower muscle mass and bone density (3). Consuming excess cortisol is definitely not going to help us lower our stress levels, and no one needs more stress in their lives.
Our tip to you: While dairy-laden meals have been shown to increase cortisol, research shows that barley soup and vegetable stir-frys with rice can lower levels of this high stress hormone (4).
References →
1. Malekinejad H, Rezabakhsh A. Hormones in Dairy Foods and Their Impact on Public Health – A Narrative Review Article. Iran J Public Health. 2015;44(6):742–758.
2. Björntorp P. Do stress reactions cause abdominal obesity and comorbidities? Obes Rev. 2001; 2(2):73-86.
3. Schorr M, Lawson EA, Dichtel LE, Klibanski A, Miller KK. Cortisol Measures Across the Weight Spectrum. J Clin Endocrinol Metab. 2015;100(9):3313–3321.
4. Gibson EL, Checkley S, Papadopoulos A, Poon L, Daley S, Wardle J. Increased salivary cortisol reliably induced by a protein-rich midday meal. Psychosom Med. 1999; 61(2):214-24.
INSULIN-LIKE GROWTH FACTOR-1
Milk naturally contains a hormone called Insulin-like Growth Factor-1 (IGF-1), a growth stimulating hormone. The whey protein naturally present in milk further stimulates our body’s production of IGF-1 by a pathway called mTOR, further increasing our circulating levels of this hormone (1). Consuming cows’ milk leads to a 10–20% increase of circulating IGF‐1 in adults, and to a 20–30% increase in children (3).
We need IGF-1 is involved in the maturation and differentiation of many cells and organs; in other words, it is vital for growth and development. However, excess IGF-1 from consumption of cows’ milk can interfere with these processes and has been associated with accelerated linear growth, altered fetal development, atherosclerosis, weight gain, acne, autoimmunity, and even neurodegenerative diseases (3). Additionally, IGF-1 receptors are present on most cancer cells. Excess IGF-1 can bind to these receptors and stimulate cancer cells to grow more quickly (2). This may explain why IGF-1 has been linked to breast, cervical, ovarian, endo‐metrial, colorectal and prostate cancers (2,3).
Our tip to you: IGF-1 is a goldilocks hormone whereby you don’t want too much, and you don’t want too little. Exercise and, in particular, strength training is a great way to naturally boost your IGF-1 levels without causing excess. Removing dairy products is a simple and effective way to control IGF-1 and reduce your risk of cancer, type 2 diabetes, and acne. Watch this video to hear from Dr. Milton Mills on how cows’ milk does NOT do a body good!
References →
1. Melnik BC, John SM, Carrera-Bastos P, Cordain L. The impact of cow’s milk-mediated mTORC1-signaling in the initiation and progression of prostate cancer. Nutr Metab (Lond). 2012; 9(1):74.
2. Melnik BC, John SM, Schmitz G. Over-stimulation of insulin/IGF-1 signaling by western diet may promote diseases of civilization: lessons learnt from laron syndrome. Nutr Metab (Lond). 2011;8:41.
3. Melnik, B. Milk consumption: aggravating factor of acne and promoter of chronic diseases of Western societies. JDDG: Journal der Deutschen Dermatologischen Gesellschaft 2009; 7: 364-370.
Cardiovascular Health and Inflammation
Years of research has told us that consuming foods high in saturated fats, like dairy products, can be detrimental to our cardiovascular health. Most recently, a 2018 study published in Laboratory Investigation not only found changes in size and shape of red blood cells just one hour after consuming a high-fat milkshake, but also changed in our immune cell function, setting the stage for inflammation, plaque formation and ultimately heart disease (1).
Not only do dairy foods contain a significant amount of saturated fat, but also more than 2% of dairy’s calories come from trans fats (2), a substance deemed as the most harmful fat in our food supply by the Institute of Medicine (3). So harmful, in fact, that there is no upper limit of these fats since any trans-fats increases risk of Cardiovascular Heart Disease. Trans fats cripple arteries, cutting blood flow to our muscles and promoting inflammation and heart disease (4).
Finally, cows’ milk contains proteins (5) and other foreign components, including sugars such as Neu5gc (6), that many people’s bodies do not recognize, initiating an immune response and promoting further inflammation. (7)
Our tip to you: While the dairy industry is adamant about promoting chocolate milk as a recovery beverage, this sugary drink is far from a health food. Antioxidant-rich foods are a far better alternative, as antioxidants stimulate cardiovascular health, athletic performance, and a speedy recovery by combattin damage done to your cells during your workout. And those are found in plant sources, not dairy food. So, eat more berries instead of dairy! Berries boost artery function and soothe inflammation (8). This will help you perform better and recover faster.
References
1. Benson TW, Weintraub NL, Kim HW, et al. A single high-fat meal provokes pathological erythrocyte remodeling and increases myeloperoxidase levels: implications for acute coronary syndrome. Lab Invest. 2018; 98(10):1300–1310.
2. USDA: Fat and Fatty Acid Content of Selected Foods Containing Trans-Fatty Acids.
3. Institute of Medicine: Dietary Reference Intakes.
4. Mozaffarian D, Katan MB, Ascherio A, Stampfer MJ, Willett WC. Trans fatty acids and cardiovascular disease. N Engl J Med. 2006; 354(15):1601-13. Review.
5. Shek LP, Bardina L, Castro R, Sampson HA, Beyer K. Humoral and cellular responses to cow milk proteins in patients with milk-induced IgE-mediated and non-IgE-mediated disorders. Allergy. 2005 Jul;60(7):912-9
6. Dhar C, Sasmal A and Varki A. From “Serum Sickness” to “Xenosialitis”: Past, Present, and Future Significance of the Non-human Sialic Acid Neu5Gc. Front. Immunol, 2019; 10:807
7. Samraj Annie, Läubli Heinz, Varki Nissi, Varki Ajit.Involvement of a Non-Human Sialic Acid in Human Cancer. Frontiers in Oncology, 2014; 4:33
8. Basu A, Rhone M, Lyons TJ. Berries: emerging impact on cardiovascular health. Nutr Rev. 2010; 68(3):168–177.
“The biggest way I saw my performance change when I dropped dairy was in my recovery. I think I would want to tell future olympians to try something other than cow’s milk, that it’s not necessary. In fact, ditching it would actually help them.”
Hall of Fame Soccer Player, Holistic Nutritionist and Switch4Good Athlete