Goat's milk is a nutrient-dense food with a composition that may offer health benefits, including aiding weight loss and improving metabolic health. While often overlooked, goat's milk presents a unique alternative to cow's milk and plant-based options, with potential advantages for certain individuals.
Nutritional Composition and Bioactive Compounds
Goat’s milk is a rich source of bioactive compounds (peptides, conjugated linoleic acid, short chain fatty acids, monounsaturated and polyunsaturated fatty acids, polyphenols such as phytoestrogens and minerals among others) that exert important health benefits. Goat milk stands out due to its high nutritional value and the presence of several bioactive compounds, including peptides, conjugated linoleic acid, short-chain fatty acids, monounsaturated and polyunsaturated fatty acids, and polyphenols like isoflavones. These compounds contribute to the functional properties of goat milk, positioning it as a functional food. Goat milk is an excellent source of protein, calcium, potassium, phosphorus, magnesium, and vitamin A. Consuming enough vitamin A can help reduce your risk of cataracts and certain forms of cancer, and even help children fight off measles.
A one-cup serving of whole goat milk contains:
- Calories: 168
- Protein: 9 grams
- Fat: 10 grams
- Carbohydrates: 11 grams
- Fiber: 0 grams
- Sugar: 11 grams
Impact of Goat Feed on Milk Composition
Goat’s milk composition depends on the type of food provided to the animal. The abundance of bioactive compounds in milk depends on the dietary sources of the goat feed. The handling and variety of food provided to goats (grazing, organic feeding, strategic supplementation, etc.) determines the quality of milk. Grazing management increases the content of polyunsaturated fatty acids of milk with respect to goats fed a conventional diet. Inclusion of Acacia farnesiana (AF) pods boosted the polyphenol content and increased the n−3:n−6 fatty acids ratio, improving the quality and functional potential of milk.
Goat Milk and Weight Management: Evidence from Studies
Recent research reveals that intake of high-fat milk and dairy products have no association with the occurrence of CVD, stroke, coronary heart disease, dyslipidemia or type 2 diabetes. Moreover, milk intake provides health benefits in subjects with diabetes, obesity and metabolic syndrome in particular with fermented dairy.
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One study evaluated the effect of milk from goats fed a conventional diet, a conventional diet supplemented with 30% Acacia farnesiana (AF) pods or grazing on metabolic alterations in mice fed a HF diet. The incorporation of goat’s milk in the diet decreased body weight and body fat mass, improved glucose tolerance, prevented adipose tissue hypertrophy and hepatic steatosis in mice fed a HF diet. These effects were associated with an increase in energy expenditure, augmented oxidative fibers in skeletal muscle, and reduced inflammatory markers. Consequently, goat’s milk can be considered a non-pharmacologic strategy to improve the metabolic alterations induced by a HF diet.
To evaluate the effect of goat milk intake in the development of obesity and its metabolic consequences, mice were fed with a control diet (control), a high fat diet (HF) or a HF diet supplemented with lyophilized milk from goats fed a conventional diet (HFCD), grazing (HFG) or a conventional diet supplemented with Acacia farnesiana pods (HFAF) for 14 weeks. As expected, at the end of the study, mice fed the HF diet showed a significant increase in body weight with respect to those fed the control diet. Interestingly, the three groups of mice fed HF diet supplemented with goat milk (HFCD, HFG, and HFAF) presented similar body weight to those fed the control diet throughout the study period. The lower final body weight of mice fed goat milk with respect to those fed the HF was not caused by a reduction in food or energy intake. Mice fed HFCD, HFG or HFAF had higher food intake than those fed the HF. Since HF diets are more energy-dense than the control diet, energy intake of mice fed either diet containing goat milk was higher than those fed control or HF diets. The increased body weight of HF mice was due to a significant increment in body fat mass and reduced lean mass with respect to control. Notably, mice fed goat’s milk presented no significant differences in fat and lean mass with respect to control except the HFCD group that had lower fat mass and higher lean mass than all other groups.
These results indicate that consumption of goat milk prevents fat accretion and body weight gain and decreases serum leptin and triglycerides levels of mice fed a HF diet despite increased energy intake.
Impact on Glucose Tolerance and Insulin Sensitivity
Chronic consumption of a high-fat diet induces metabolic derangements such as glucose intolerance and insulin resistance. Fasting serum glucose was higher in the HF mice when compared to controls and mice fed HFCD. Mice fed HFG and HFAF had no significant difference in fasting glucose concentration with respect to HF or control groups. However, fasting serum insulin at the end of the study was significantly lower in all groups fed goat milk than in those fed the HF or control diets.
Mice fed with either goat’s milk had the same glucose tolerance than control. As expected, mice fed HF had a blunted response to exogenous insulin reflected by a higher AUC. Interestingly, the glucose curve of mice fed goat’s milk during the ipITT challenge was lower than those fed HF and similar to that of control mice. The AUC of all groups fed goat milk had a trend to be lower than that of the HF, but only in HFAF was significantly lower than the other groups.
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These results indicate that goat’s milk decreases HF-associated glucose intolerance, preventing hyperinsulinemia. Notably, the lower insulin concentration of mice fed goat milk was associated with a decrease in HF-induced pancreatic islet hypertrophy, since HFCD, HFG and HFAF mice presented pancreatic islets size similar to those from control mice. Altogether, these results indicate that goat’s milk intake attenuates glucose intolerance and hyperinsulinemia associated to a decrease in pancreatic islet size in mice fed a HF diet.
Energy Expenditure and Substrate Utilization
To evaluate whether the lower body weight and fat mass, and the improvement on glucose tolerance observed in HF mice fed goat’s milk was associated with increased energy expenditure, oxygen consumption was evaluated by indirect calorimetry using a CLAMS system. As expected, HF mice had lower average oxygen consumption than control mice in both fasting and feeding conditions. Interestingly, HFCD, HFG and HFAF mice presented significantly higher oxygen consumption than HF and control mice in fed conditions, indicating an increase in energy expenditure. When oxygen consumption was calculated per Kg of lean mass, only de HFAF group had higher oxygen consumption than the rest of the groups.
HFCD, HFG, and HFAF mice presented a significantly higher RER than HF mice, indicating an improvement on substrate utilization. The lower RER of mice fed goat’s milk with respect to those fed the control diet indicates that these mice uses fatty acids as an energy substrate even during the feeding period.
Maintenance of a stable body weight despite a positive energy balance in response to consumption of an energy-dense diet is achieved by increased energy expenditure.
Advantages of Goat Milk
- High in Digestible Protein: Goat milk has more protein per serving than standard cow milk, soy milk, or nut milks. The protein in goat milk appears to be more digestible, meaning your body can use it more easily.
- May Not Provoke Milk Allergies: Some people with allergies to cow milk may find that goat milk doesn’t trigger their allergies.
- Managing Cholesterol Levels: Goat milk may help reduce cholesterol levels in people with high blood cholesterol. Studies have shown that goat milk can help reduce cholesterol in the arteries and gallbladder.
- Easier to Digest: Goat’s milk is easier to digest because it is made up of small fat particles, much smaller than those found in cow’s milk, making them easier to break down and assimilate into the blood stream. Plus, these small fat particles form a softer smaller curd in the stomach. These soft small curds are more quickly broken down by stomach enzymes, making it easier for the stomach to digest as compared to cow’s milk.
- Medium Chain Fatty Acids: Goat’s milk contains twice the amount of medium chain fatty acids as compared to cow’s milk. These fatty acids are used to make energy and aren’t stored as fat, which is why it can actually lower cholesterol and help with conditions like heart disease and intestinal disorders.
- Bioavailability of Minerals: The minerals found in goat’s milk are more bioavailable, which means that they too are also easier to digest and absorb into the cells than cow’s milk. In fact, both cow’s milk and goat’s milk are rich in calcium, but the calcium in goat’s milk is easier to absorb.
- Antimicrobial Properties: Goat’s milk is famous for its anti-bacterial and anti-fungal properties and even has anti microbial activity against staph aureus, which causes diseases like pneumonia, UTI’s, sinusitis, infective endocarditis, and osteomyelitis. It even has anti-bacterial properties against E. Therefore it plays a huge role in GI protection.
- Selenium Content: Cow’s milk contains trace amounts of selenium but there are very high amounts of it in goat’s milk, which is also important for our immune systems to fight off infections. Selenium is also used by the thyroid gland to make its hormones as is iodine, which is also found in goat’s milk.
Disadvantages and Considerations
- Not Lactose-Free: Goat milk still contains lactose, just like cow milk. If you are lactose-intolerant, goat milk is not for you.
- More Calories than Cow or Plant Milk: Goat milk has more calories per serving than any other types of milk. Consuming too many calories can lead to weight gain.
- Infants: “Goat milk can be a great supplement for children and adults, but is not appropriate for infants. In the early 1900s, infants fed primarily goat milk would commonly develop anemia from the lack of folate and B12. The problem was so prevalent that it was nicknamed ‘Goat milk anemia,'”
- Milk Protein Allergies: “Many people who are allergic to cow milk will also be to goat milk.
Fermented Goat Milk
Fermentation of goat milk or derived products, such as cheese, can potentiate its benefits or create new ones. Fermentation is traditionally driven by the lactic acid bacteria (LAB) starters Streptococcus thermophilus and Lactobacillus bulgaricus, and can potentially reduce the “goaty” flavor, improve the consumers’ acceptability and carry beneficial probiotics.
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FGM using conventional yogurt starters presented a fatty acid profile that is considered more health-promoting when compared with fermented cow milk: lauric, oleic, and linoleic acids are found in higher levels. Oleic and linoleic acid have insulin-sensitizing and lipid-lowering properties, reducing blood triglyceride and LDL cholesterol in animal models through their anti-inflammatory activity. FGM showed lower amounts of myristic and palmitic acids when compared to raw goat milk. These are fatty acids associated with higher CVD risk.
In Vitro Evidence of Anti-Obesity Properties
Certain components of FGM may have functional properties that improve CVD biomarkers. The anti-atherogenic properties of the lipid fraction of goat milk, yogurt, and cheese obtained through the fermentation by S. thermophilus and Lactobacillus bulgaricus were evaluated by Poutzalis et al. (2015). These authors reported that the total lipids and the polar lipids fractions of all three dairy products had inhibitory activities against platelet-activating factor (PAF)-induced platelet activation. Angiotensin I-converting enzyme (ACE)-inhibitory activity is one of the most studied functional characteristics of bovine and goat dairy products. This ACE-inhibition activity is attributed to casein-derived peptides, which were purified from Lacticaseibacillus casei NK9-FGM (Parmar et al., 2017), goat milk kefir (Quirós et al., 2005) and cheese.
In Vivo Evidence of Anti-Obesity Properties
At present, FGM products are scarcely evaluated through in vivo obesity models. Altamimy et al. (2022) observed that the administration of naturally-fermented goat milk (an artisanal product named…