Autism spectrum disorder (ASD) could be actively linked to gastrointestinal disorders, selectivity in the food consumption, lactose intolerance, and the possible sensitivity to the proteins of cow milk, especially casein. These issues have made nutritionally adequate, cow milk substitutes of children in follow up of casein-free dietary interventions. The present review aimed to look at the possible alternatives to cow milk with focus given to nutritional composition, digestibility, allergenicity, environmental sustainability, and practicality to children living with ASD. A narrative review of 39 peer-reviewed studies published between 2003 and 2025 was carried out via Google Scholar, PubMed, Scopus, as well as, Science Direct. Key terms in the search were: casein protein of cow’s milk, plant-based milk alternatives, milk substitutes, and specific alternatives like soy, almond, oat, rice, pea, and coconut milk. The results suggest that plant-based and select animal-derived milk alternatives can be used to support casein-free dietary management; though, the nutritional value of these milk alternatives differ significantly. Most soy and pea-based milks tend to have higher protein content, whereas most nut, cereal, seed, and pseudo-cereal based milks may require dietary fortification or complementary foods to support the intake needs of calcium, vitamin D, vitamin B12, and essential amino acids. Proper derived processing techniques such as fermentation process, sprouting, cooking, enzyme hydrolysis may enhance digestibility and nutrient bioactivity. Careful dietary planning and professional supervision are recommended.

• Autism spectrum disorder (ASD)

• Substitute for cow’s milks

• Casein protein of cow’s milk

• Plant-based substitutes

Hasan M, Akter S (2026) Substitute for Casein Protein in Cow’s Milk of Children with Autism Spectrum Disorder: A Review. J Autism Epilepsy 7(1): 1022.

As of recent estimates, approximately 1 in 100 children globally, which equates to about 1% of the worldwide population, are diagnosed with autism spectrum disorder (ASD). Many parents of children with ASD implement a gluten-free and casein-free (GFCF) diet for their children, hoping to alleviate their maladaptive symptoms. Numerous therapies are available to assist in reducing these maladaptive symptoms, enabling individuals to pursue a more typical and independent lifestyle.

Casein-free Milk and Diet

The casein-free diet represents a nutritional approach that may be advantageous for certain individuals with autism, especially in alleviating gastrointestinal symptoms and particular behavioral challenges. This diet entails the removal of casein, a protein predominantly present in the liquid component of cow’s milk and its derived products (such as milk, cheese, yogurt, ice cream, etc [1]. Similar to the gluten-free diet (GFD), the casein-free diet is founded on hypotheses proposing a connection between dietary proteins and the manifestations of autism symptoms [2].

Rationale for Cow’s milk Casein-free Diet in Autism

Leader et al. [3], demonstrated some people with autism have an increased sensitivity or allergy to casein. This can lead to digestive issues and inflammation, which can worsening symptoms of autism. Whilst digesting, casein can produce peptides that act like opioids (known as casomorphins), just like gluten. These peptides can potentially enter the brain and influence function and behavior in autism spectrum disorder [4]. The theory of the “gut-brain axis” proposes that the health of the gut is strongly linked to the health of the brain, and casein could be involved in this process. Casein can make the gut irritated, increasing the permeability of the gut, known as “leaky gut”, and allow substances to enter the bloodstream and cause changes in the brain and behaviour [5]. Therefore, alternative (casein-free diets) should be considered. These aim to prevent casein from reaching the bloodstream, which may alleviate the behavioural and cognitive issues associated with autism [6].

To narrow the scope of this review, the focus will be on plant-derived milk products to counteract the limited research in this area. Dairy substitutes derived from plants include milk, yogurt, cream, ice cream, butter and cheese [6]. These dairy substitutes are sourced from one of five main categories of plants: grains, legumes, vegetables, seeds and nuts [7]. The nutritional value and healthiness of plant dairy substitutes are debated [8]. It is well known that dairy products are a good source of a range of nutrients such as protein, vitamin D, calcium and magnesium [7]. But in terms of children’s nutrition, it is argued that plant-based dairy alters may contain more of these nutrients, and in a more bioavailable form than dairy products [6]. Overall, many health professionals argue that while dairy is the better choice, plant-based dairy could still be part of a balanced diet [8]. Given that children are the future generation, they play a critical role in the world (De-Magistris & Uldemolins, 2022). As such, to encourage a more sustainable future, it’s essential to teach them about following dietary principles that prioritise plant based foods.

Usefulness and Implementation of a Casein-free Milk and Diet

Transitioning to a diet free of casein necessitates thorough preparation to maintain adequate nutrition. This approach excludes all sources of casein like milk, cheese, yogurt, butter, and various dairy products, along with hidden forms found in processed foods [9]. Caregivers may use casein-free alternatives such as almond milk, soy milk, rice milk, coconut milk, and cheese substitutes without casein to sustain a well-rounded diet. Parents and guardians have noted a decrease in hyperactivity, irritability, and repetitive actions [10]. For certain individuals diagnosed with ASD, following a casein-free diet may improve overall well-being through better health and symptom control. Moreover, findings from supporting studies suggest that implementing a gluten-free and casein-free diet in children diagnosed with Autism Spectrum Disorder notably lessens the occurrence of maladaptive symptoms. Research conducted by [11,12], Pedersen et al., and Whiteley et al., shows considerable declines in maladaptive symptoms utilizing various behavioral assessment techniques.

Certain targeted dietary changes, including the removal of specific foods, can help some individuals with autism by identifying and eliminating possible allergens or irritants, which may assist in alleviating gastrointestinal symptoms and some behavioral problems. Thus, dietary modifications and treatments are essential in enhancing the health and quality of life for those with ASD [13].

This review aims to conduct an overview of Substitute for Cow’s Milk, including nutrient composition (macronutrients and micronutrients), allergens, market sales, environmental sustainability and reality.

They consist of aqueous extracts derived from legumes, grains, pseudo grains, oilseeds, vegetables, and nuts. The demand for Plant-Based Milk Alternatives (PBMAs) continues to grow as an increasing number of individuals transition from dairy to plant-based diets, viewing them as nutritious, environmentally friendly, free from casein proteins, and produced without harm to animals. The categorization according to different groups is provided in Table 1.

Table 1: Classification of Plant Based Milk Alternatives based on categories.

Protein is an essential macronutrient, here may be a lot of protein in milk, but that doesn’t mean that it doesn’t exist anywhere else. It does! And vegans simply do what elephants, bison and rhinos do. So, it’s important to be aware of what plant-based milks are protein-rich, and to include a variety of plant-based milk proteins in your meals. Above issues do the clear that-

All essential amino acid: Cow’s milk protein contains all the essential amino acids, on the other hand plant proteins vary widely in concentration and amino acid balance. Legumes are rich in lysine but low in methionine, while cereals show the opposite trend. Combining these sources achieves a complementary amino acid profile similar to animal proteins that we need. Interestingly, Quinoa contains all nine essential amino acids [14].

Bioactive Components: Plant proteins contain naturally occurring compounds such as polyphenols, phytosterols, dietary fiber, and antioxidants, which contribute cardio-metabolic and anti-inflammatory benefits for children with ASD.

Nutritional Prospective of Substitute for Cow’s Milk

Yang et al. [15], emphasized the components of autistic children’s blood and tissue reveals they have lower levels of important nutrients, such as: Vitamins B12, Vitamin C, Vitamin D, Calcium, Iron, Magnesium, and Zinc.

These deficiencies, often stemming from selective eating habits, sensory sensitivities, and GI issues, can exacerbate the core symptoms of ASD and lead to additional health complications. The overall protein, fat, and nutrient profile depend on the base ingredient. Fat content varies across both dairy and plant-based milks. Soy and pea milks tend to contain higher protein levels comparable to cow’s milk, whereas almond, rice, oat, and coconut milks often provide minimal protein and energy.

Oat milk is a more affordable source of zinc and riboflavin but is lower in protein, calcium, and potassium. Other side, Almonds and sesame milk are naturally rich in calcium, zinc, potassium, and magnesium (Table 2). Besides plant milk also contains fiber and omega-3 which is very rare in liquid parts of cow’s milk; Fiber plays a crucial role in maintaining bowel regularity by promoting bulk formation and stool softening [15], and omega-3 fatty acid to improve neuronal function, lower inflammation, and balance neurotransmitters to help control the immunological response in the brain of child with ASD [16].

Table 2: Average nutrients in dairy and plant-based milks [17].

Health Prospective

Digestive Tolerability and Behavioral Considerations in autism: The Lefter et al. [18], study reports that as much as 70% of those with ASD have GI symptoms such as stomach pain, constipation, diarrhoea, bloating and gastroesophageal reflux (GERD). These have 

been reported to be more frequent and severe in ASD compared to a non-ASD population.

Casein, being a gut irritant, may lead to leaky gut (firstly in the gut then in the brain) and the release of toxins - which subsequently impact on behaviour [5]. GI problems may worsen ASD-related behavioural symptoms, such as irritability, aggression, and repetitive behaviours [19].

Addressing these GI issues are important in improving the quality of life and health outcomes of people with ASD, as the conditions may require individualised treatment, with a consideration for their sensory and dietary preferences.

Lactose Intolerance of Children with ASD: Lactose intolerance is a common problem affecting the digestion of lactose. Autistic children generally present with a higher tendency towards lactose intolerance than neurotypical children. In a recent study, the Lactase Deficiency rate was 58% in children with autism under 5 years, and 65% in older people with autism [20]. This can lead to a number of gastrointestinal symptoms, including gas, bloat and constipation. These issues can exacerbate abdominal pain which is a major issue for many children on the autism spectrum. Excluding lactose from the diet of a child with autism may improve not only gastrointestinal symptoms, but may also improve traits of autism.

Pus: Many dairy cows suffer from mastitis, or a bacterial infection of the udder, causing painful swelling or hardness. This painful disease is commonly associated with dirty, inadequate and poorly ventilated housing. There can be as many as 70 cases of mastitis per 100 cows per year in the UK [21].

In response to mastitis, a cow’s body produces more “policemen” (white blood cells) to fight infection, which ends up in the milk. These are known as somatic cells or pus. The greater the number of somatic cells, the greater the risk of udder infection. Since mastitis is common in 

dairy cows it cannot be completely eliminated, and the EU legal limit for pus in milk (consumed by people) is 400,000 cells per litre [22].

New infectious threats to health: Livestock production is now a source of new infectious disease risks, which can result in human epidemics and pandemics at any time. Antibiotic use in animal farming plays a major role in the rise of antibiotic-resistant infections, which again pose a threat to human health. It’s now understood internationally we need to switch to a plant-based diet to maintain health in both humans and the environment. Hana Kahleova, MD, PhD, who is the director of clinical research at the Physicians Committee for Responsible Medicine and the lead author of the study, stated that eating acid-producing foods (such as meat, dairy and eggs) can raise dietary acid load (amount of acid consumed) which in turn results in inflammation [23].

Environmental Sustainability

A significant investigation conducted by Oxford University evaluated the ecological consequences of the most frequently consumed food items from 40,000 diverse farms in 119 nations. The research revealed that the carbon emissions associated with producing cow’s milk are threefold compared to those from any plant-based milk. Additionally, it indicated that dairy production requires substantially more land and a considerable amount of water an astonishing 22 times more than the water needed for soya milk (Poore & Nemecek, 2018). Moreover, one of the primary researchers, Joseph Poore, stated: “Refraining from consuming animal products yields considerably greater environmental advantages than opting for sustainable meat and dairy.” Therefore, plant-based milk is the most environmentally-friendly option - including almond milk, despite its high water usage.

Marketing Prospective of Substitute for Cow’s Milk

The market for plant-based milks has grown phenomenally over the past 10 years and has rapidly become a multi-billion-dollar industry in the United States and across the globe [24,7]. One of the factors fuelling this growth has been the perception among consumers that these alternatives to milk offer similar (or even better) nutritional qualities to cow milk [25]. This perception is heavily influenced by the term milk as part of labels and placement of these products next to cow milk in dairy aisles in supermarkets. So, it seems that everything that cows can provide, plants can provide even more of.

Reality: The White Truth of Cow Milk

Dr. Biswaroop Roy Chowdhury (www.biswaroop.com) 

[26], he is best known for developing the popular research based D.I.P. Diet plan, describes that, Human is the only species who drinks milk all life long and human is the only animal who drinks milk of other animals! Never seen a tiger drinking a cow’s milk! Humans have infringed the nature by consuming milk which was intended for child of that animal. It’s not that surprising that humans are the only animals who suffer from diabetes, heart diseases, cancer and various other deadly diseases.

“Myth 1 claims dairy is essential for strong bones, but the truth shown here is that countries with high dairy intake (Finland, Sweden, Denmark) still have osteoporosis, while Vietnam and Thailand with low dairy intake have fewer bone diseases. Myth 2 says dairy is full of nutrition and calcium; truth: calcium ultimately comes from plants, cows get it from greens, and humans can obtain nutrition from plant sources, with milk not being necessary. Myth

3 asserts that milk promotes growth; truth: cow milk contains growth hormones much higher than human milk, and very rapid growth isn’t necessarily good, with some links claimed between high dairy consumption and cancer. The piece also promotes a “3 Weeks Drop Dairy Challenge” promising dramatic health improvements, though such claims should be viewed with skepticism”

In addition, Large dietetic association’s globally, such as the British Dietetic Association (BDA) in the United Kingdom have stated that a 100% plant-based diet can provide all the nutritional requirements for the life cycle from infancy to adulthood [27]. A recent study was done by [28] in New Zealand among 143 individuals and 18 PBMA samples. An exploratory analysis was performed to investigate the relationship between energy, protein, fat and carbohydrate content, but found no difference.

These aforementioned facts have made the use of plant-based milks (vegetables, pulses, fruits, legumes, seeds, and cereals) increase due to several reasons, such as attitudes of the environmentally conscious attitude, abhorrence to animal cruelty and maintenance of a healthy diet. Therefore, the growth of plant-based dairy products has grown up to 61 % from 2012 [29].

A potential challenge with substitute for cow’s milk or diets is the lack of important macro and micronutrients compared to cow’s milk, such as essential protein, calcium, vitamins D, B12 and, along with the problems of more anti-nutrients, allergens and tastelessness. But the comforting thing is that alternative and emerging technologies can overcome these challenges in Table-3.

Table 3: Challenge with substitute for cow’s milk of children with Autism and their Mitigation plan

So, which is better in these reviews: substituted or cow’s milk? The reality is that, substitute for cow milk require fewer resources to produce, have a smaller environmental footprint and allergenic-caseins-lactose free suitable for Children specially child with ASD. Nevertheless, transitioning to a casein-free milk or diet requires careful planning to ensure nutritional adequacy. A balanced diet combining whole grains and legumes provides all essential Protein. Other side, cooking reduces inhibitors, fermentation enhances nutrients, sprouting activates enzymes, and hydrolysis boosts digestibility is the good step to minimize anti-nutrients and allergens properties. Over all, it is true to say that dairy products are not an essential part of our diet and whether dairy products should be considered ‘nutritional value’ is debatable. As a result, caregivers need to be informed about alternatives to cow’s milk for organizing meals, shopping for groceries, and cooking dishes that fulfill the dietary requirements of those with ASD. Organizations ought to provide training focused on alternatives to cow’s milk. Regulatory agencies should establish guidelines regarding this matter, in addition to researchers needing to investigate this field.

1. Baspinar B, Yardimci H. Gluten-Free Casein-Free Diet for Autism Spectrum Disorders: Can It Be Effective in Solving Behavioural and Gastrointestinal Problems? Eurasian J Med. 2020; 52: 292-297.
2. Piwowarczyk A, Horvath A, ?ukasik J, Pisula E, Szajewska H. Gluten-and casein-free diet and autism spectrum disorders in children: a systematic review. Eur J Nutr. 2018; 57: 433-440.
3. Leader G, Abberton C, Cunningham S, Gilmartin K, Grudzien M, Higgins E, et al. Gastrointestinal Symptoms in Autism Spectrum Disorder: A Systematic Review. Nutrients. 2022; 14: 1471.
4. Thiruvengadam M, Venkidasamy B, Thirupathi P, Chung IM, Subramanian U. β-Casomorphin: A complete health perspective. Food Chem. 2021; 337: 127765.
5. Alharthi A, Alhazmi S, Alburae N, Bahieldin A. The Human Gut Microbiome as a Potential Factor in Autism Spectrum Disorder. Int J Mol Sci. 2022; 23: 1363.
6. Adamczyk D, Jaworska D, Affeltowicz D, Maison D. Plant-Based Dairy Alternatives: Consumers’ Perceptions, Motivations, and Barriers-Results from a Qualitative Study in Poland, Germany, and France. Nutrients. 2022; 14: 2171.
7. Bridges M. Moo-ove Over, Cow’s Milk: The Rise of Plant-Based Dairy Alternatives. Pract Gastroenterol. 2018; 21: 20-27.
8. Clark BE, Pope L, Belarmino EH. Perspectives from healthcare professionals on the nutritional adequacy of plant-based dairy alternatives: results of a mixed methods inquiry. BMC Nutr. 2022; 8: 46.
9. Marí-Bauset S, Zazpe I, Mari-Sanchis A, Llopis-González A, Morales-Suárez-Varela M. Evidence of the gluten-free and casein-free diet in autism spectrum disorders: a systematic review. J Child Neurol. 2014; 29: 1718-1727.
10. Pennesi CM, Klein LC. Effectiveness of the gluten-free, casein-free diet for children diagnosed with autism spectrum disorder: based on parental report. Nutr Neurosci. 2012; 15: 85-91.
11. Herbert MR, Buckley JA. Autism and dietary therapy: case report and review of the literature. J Child Neurol. 2013; 28: 975-982.
12. Knivsberg AM, Reichelt KL, Høien T, Nødland M. Effect of dietary intervention on autistic behavior. Focus Autism other Dev Disabil. 2003; 18: 248-257.
13. Hartman RE, Patel D. Dietary Approaches to the Management of Autism Spectrum Disorders. Adv Neurobiol. 2020; 24: 547-571.
14. Alsaleem KA, Moftah RF, El-Geddawy MMA. New Insights into Red and White Quinoa Protein Isolates: Nutritional, Functional, Thermal Properties. Processes. 2024; 12: 2822.
15. Yang J, Wang HP, Zhou L, Xu CF. Effect of dietary fiber on constipation: a meta analysis. World J Gastroenterol. 2012; 18: 7378-7383.
16. Bent S, Bertoglio K, Ashwood P, Bostrom A, Hendren RL. A pilot randomized controlled trial of omega-3 fatty acids for autism spectrum disorder. J Autism Dev Disord. 2011; 41: 545-554.
17. USDA, 2019. Agricultural Research Service. Food Data Central.
18. Lefter R, Ciobica A, Timofte D, Stanciu C, Trifan A. A Descriptive Review on the Prevalence of Gastrointestinal Disturbances and Their Multiple Associations in Autism Spectrum Disorder. Medicina. 2019; 56: 11.
19. Fulceri F, Morelli M, Santocchi E, Cena H, Del Bianco T, Narzisi A, et al. Gastrointestinal symptoms and behavioral problems in preschoolers with Autism Spectrum Disorder. Dig Liver Dis. 2016; 48: 248-254.
20. Kushak RI, Lauwers GY, Winter HS, Buie TM. Intestinal disaccharidase activity in patients with autism: effect of age, gender, and intestinal inflammation. Autism. 2011; 15: 285-294.
21. NADIS. NADIS Animal Health Skills – Part 5: The Impact of Mastitis and Lameness on Fertility. 2015.
22. AHDB. Somatic Cell Count, an Indicator of Milk Quality. 2025.
23. Kahleova H, Znayenko-Miller T, Smith K, Khambatta C, Barbaro R, Sutton M, et al. Effect of a Dietary Intervention on Insulin Requirements and Glycemic Control in Type 1 Diabetes: A 12-Week Randomized Clinical Trial. Clin Diabetes. 2024; 42: 419-427.
24. Jeske S, Zannini E, Arendt EK. Evaluation of Physicochemical and Glycaemic Properties of Commercial Plant-Based Milk Substitutes. Plant Foods Hum Nutr. 2017; 72: 26-33.
25. Singhal S, Baker RD, Baker SS. A Comparison of the Nutritional Value of Cow’s Milk and Nondairy Beverages. J Pediatr Gastroenterol Nutr. 2017; 64: 799-805.
26. Dr. Biswaroop Roy Chowdhury. 2025.
27. https://www.bda.uk.com/resource/vegetarian-vegan-plant-based-diet.html
28. Jaeger SR, Dupas de Matos A, Frempomaa Oduro A, Hort J. Sensory characteristics of plant-based milk alternatives: Product characterisation by consumers and drivers of liking. Food Res Int. 2024; 180: 114093.
29. Reyes-Jurado F, Soto-Reyes N, Dávila-Rodríguez M, Lorenzo-Leal AC, Jiménez-Munguía MT, Mani-López E, et al. Plant-based milk alternatives: Types, processes, benefits, and characteristics. Food Rev Int. 2023; 39: 2320-2351.
30. Shabo Y, Yagil R. Etiology of autism and camel milk as therapy. Int J Disabil Human Dev. 2005; 4.
31. Clem J, Barthel B. A Look at Plant-Based Diets. Mo Med. 2021; 118: 233-238.
32. Nelson ER. Eight Secrets of Health. 1994: 215.
33. Grembecka M, Szefer P. Elemental Profiles of Legumes and Seeds in View of Chemometric Approach. Appl Sci. 2022; 12: 1577.
34. Messina M. Soy foods, isoflavones, and the health of postmenopausal women. Am J Clin Nutr. 2014; 100: 423S-430S.
35. Phillips KM, Horst RL, Koszewski NJ, Simon RR. Vitamin D? in mushrooms. J Agric Food Chem. 2012; 59: 7841-7853.
36. Watanabe F, Yabuta Y, Bito T, Teng F. Vitamin B??-containing plant food sources for vegetarians. Nutrients. 2014; 6: 1861-1873.
37. Marques de Brito B, Campos VM, Neves FJ, Ramos LR, Tomita LY. Vitamin B12 sources in non-animal foods: a systematic review. Crit Rev Food Sci Nutr. 2023; 63: 7853-7867.
38. Eissa HA, Mohamed SS, Hussein AMS. Nutritional value and impact of wheatgrass juice (Green Blood Therapy) on increasing fertility in male albino rats. Bull Natl Res Cent. 2020; 44: 30.
39. Watanabe F, Yabuta Y, Tanioka Y, Bito T. Biologically active vitamin B12 compounds in foods for preventing deficiency among vegetarians and elderly subjects. J Agric Food Chem. 2013; 61: 6769-6775.