Webinar | Milk and immunity

The webinar was held on April 30th, 2020. Watch the recording here:

Due to time limitation, not all questions were answered during the live webinar. As such, the speakers have addressed them below.

Q: In terms of immunogenicity, what’s the difference between full cream and low fat pasteurized milk that we get commercially from supermarkets?

A: The immunogenicity of milk is for a large part determined by the protein fraction. Processing has therefore an influence as it damages the native protein structure and functionality. The fat fraction in milk contains bioactive components (i.e. specific fatty acids, fat-soluble vitamins, phospholipids), however, it is so far not known how differences in fat composition (or the removal of fat in skimmed milk) in commercial products translate to health benefits.

Q: Will fresh milk be a better choice than UHT milk or milk powder in terms of functionally active protein? Apart from its nutritional value, are colostrum products beneficial? Does colostrum powder contain less functionally active proteins than colostrum from breastmilk?

A: In terms of nutrition, pasteurized and UHT milk are the same. In terms of protein functionality, in pasteurized milk at least 50% of the immune-related milk proteins are still functionally active, and in unprocessed milk 100% (but milk needs to be processed for safety). In UHT or powdered products it is about 0-1%. In my personal view that means that I prefer pasteurized over UHT milk. But shelf life is much shorter, so that may be a practical reason to prefer UHT. Bovine colostrum has slightly increased levels of immune active proteins compared to normal bovine milk (around factor 2 or so) , but the levels of IgG are 10-100 fold higher. I do not know how that compares to breast milk colostrum. But breast milk colostrum has high IgA levels, and bovine colostrum IgG levels. So there are differences, but typically differences that also apply to concentration level differences between human and bovine mature milk (eg. HMO levels, LF levels).

Q: From the webinar, we learn that milk contains mineral, vitamins & immune active milk components that are beneficial to immune system. Hence how if a person is lactose intolerance?

A: Lactose intolerance is related to a lack or insufficient amount of the digestive enzyme lactase that is needed to digest lactose, the main milk carbohydrate. The severity of the intolerance can differ, therefore consumption of (small amounts) of milk or milk products is possible. Some milk products contain less lactose compared to fresh milk (yoghurt, quark).

Q: What would the recommendation be for those who either claim to be lactose intolerant (but not on lactase enzymes) and those who do not prefer to drink milk (eg. elderly Asians)          

A: For either consumers that are lactose intolerant or do not prefer to drink milk, it would be advisable to include other dairy products in their daily diet (yoghurt, quark, cheese) to make sure that the intake of the beneficial milk components is still met. In lactose intolerant individuals, the intake of dairy products will depend on the threshold of their symptoms.

Q: Would like to know the differences in immunoglobulin in each type of milk (eg. low fat milk, fresh milk, flavours milk) as I do know that it depends on the temperature of pasteurization but do different type of milk will have different temperature level in heating?  

A: If the flavoured milk has a long shelf life it is typically heated with high temperature (UHT), resulting in no intact milk proteins. For pasteurized milk, the presence or absence of fat will not make a difference for the level of bioactive proteins like immunoglobulins (Ig).

Q: Want to know more about the relationship between bovine colostrum and immunity in early life nutrition    

A: To date, bovine colostrum is not used in early life nutrition products. However, we do know that colostrum from cows that are vaccinated with eg rotavirus, contains specific IgG that can help prevent infection. Before we can draw a conclusion on the consumption of regular bovine colostrum in early life nutrition products, well-designed and controlled  clinical studies should be available.

Q: Does excess milk have a side effect in the body?

A: All components that are naturally present in bovine milk are recognized as safe for consumption, so far there is no indication that over-consumption might be harmful. However, it might be possible that the total calorie intake is too high with excess milk intake, leading to undesirable weight gain. This is dependent on the total composition of the diet, the physical condition and life style of the individual.

Q: Is there any difference between cow milk and bovine milk? Are all cow milk in the market considered bovine milk? Is pasteurized milk better than UHT milk in terms of nutrition and relation to immunity?

A: Cow’s milk and bovine milk have the same meaning. The term ‘cow’ and ‘bovine’ are interchangeably used. In terms of nutrition, pasteurized and UHT milk are the same. In terms of protein functionality, in pasteurized milk at least 50% of the immune-related milk proteins are still functionally active. In my personal view that means that I prefer pasteurized over UHT milk. But shelf life is much shorter, so that may be a practical reason to prefer UHT.

Q: As far as I’m concerned, milk from cows that are fed with cornmeal are highly inflammatory, since corns are high in omega-6 fatty acids, and only those fed with grass can actually retain the original nutrients and benefit human body. So I was wondering how we can tackle this issue, or how we can identify and differentiate them from each other?

A: The composition of the feed of cows indeed influences the fat composition of the milk. Corn contains more n-6 PUFA and grass contains more n-3 PUFA. The ratio n-6/n-3 can be influenced by the contribution of the different feed types. As it is known that fatty acids from the feed may reach the milk, adapting the diet of the cow can result in lower n-6 over n-3 PUFA ratios. Alternatively, n-3 PUFA can be can be supplemented in dairy products. This is for example done in infant nutrition.

Q: As bovine colostrum is a good source of IgG, what do you think is needed for it to be approved in most countries for infant nutrition application?     

A: Application of bovine colostrum would depend on many factors. One of the reasons for not accepting it is from an animal welfare perspective: colostrum should be fed to calves. However, even if this is done, still some colostrum can be collected. But this is not always done as the price for colostrum is higher than for milk. This then may result in lower colostrum feeding to calfs. The other reason is the fact that – whereas IgG levels are 10-100 fold increased, other components are also increased like some growth factors like EGF and IGF. For this reason milk with intact IgG or isolated IgG is preferred over colostrum.

Important note

Breastfeeding is the best nutrition for healthy growth and development of babies. Exclusive breastfeeding for six months is the optimal way of feeding infants. Thereafter infants should receive complementary foods with continued breastfeeding up to two years or beyond. Mothers should receive guidance on proper maternal nutrition in order to help sustain an adequate supply and quality of breast milk. Unnecessary introduction of bottle-feeding, partially or fully, or of other complementary foods and drinks may have a negative impact on breastfeeding, which may be irreversible. Mothers should consult their doctor and consider the social and financial implications before deciding to use breast milk substitutes or if they have difficulty breastfeeding. Usage, preparation and storage instructions of breast milk substitutes or of other complementary foods and drinks should be followed carefully as improper or unnecessary use may pose a health hazard.

About the speakers

Dr. Marlotte Vonk (Ph.D in Nutritional Immunology) is a scientist in the field of infant nutrition & immunology. Currently, Marlotte works with the FrieslandCampina Research and Development team in Singapore, and is involved in early life nutrition research and product innovation.

Professor Joost van Neerven is a professor of Mucosal Immunity at Wageningen University in the Netherlands. Joost is also an immunologist with FrieslandCampina Research and his interests include (mucosal) immunology, allergy, nutrition and milk.

Live webinar

Who? Nutrition and health professionals
Costs? This webinar is provided free of charge by FrieslandCampina Institute
Language? English
Duration? 60 minutes

What will you learn?

• Introduction to the immune system
• How does milk influence immunity?
• Lessons from milk and epidemiology
• Lessons from milk and experimental research