The inclusion of soy and linseed oils in the diet of dairy cows made the fatty acid content of their milk even healthier for human consumption. It also increased the levels of omega-6 and omega-3, which, when properly balanced, play a key role in the prevention of, for example, cardiovascular disease, chronic inflammation and some types of cancer.
Cardiovascular disease is one of the world’s biggest public health problems. In Brazil they are one of the leading causes of death. According to the Ministry of Health, around 300,000 Brazilians suffer a heart attack each year, 30% of which die.
Research led by Arlindo Saran Netto, Professor at the Faculty of Animal Science and Food Technology of the University of São Paulo (FZEA-USP) in Pirassununga, State of São Paulo, shows that the consumption of these oils by dairy cows lowered the saturated fat content in their milk and the unsaturated fat content that help lower LDL known as “bad cholesterol”.
An article released reported in PLOS ONE about the results of the research that was supported by FAPESP. The study was part of a series led by Saran Netto for more than five years to improve food quality and develop novel types of milk and meat.
“The quality of the milk available on the market is good. In our research, we aim to create more ways to ensure that milk benefits human health in novel ways. Many consumers want to follow a certain diet, ”said Saran Netto FAPESP agency.
The study showed that supplementing the cow feed with these two oils resulted in an omega-6 / omega-3 ratio of 2.7: 1 in the milk. Given the opposing effects of the two fatty acids, a healthy diet should be balanced. The World Health Organization (WHO) recommends between 5: 1 and 10: 1, but 50: 1 could result from a diet consisting mostly of ultra-processed foods low in fish and vegetables, creating an imbalance and increasing the risk of heart disease increases cancer.
Like other mammals, humans cannot synthesize omega-6 or omega-3 and must get them from food. “Future studies should evaluate the health benefits of omega-fortified milk in the human diet,” the article concludes.
In the human metabolism, omega-6 and omega-3 compete for the same elongase and desaturase enzymes. Higher omega-6 levels impair the metabolism of omega-3. Too much omega-6 can increase blood pressure and triglyceride levels, among other things. Omega-3 can have anti-inflammatory effects and reduce blood lipids. Recent research has shown that diets with the right amounts of both play an important role in disease prevention.
method
The researchers worked with 18 lactating Holstein dairy cows for 94 days. All animals were fed the same diet for the first ten days, followed by three experimental periods of 28 days. The control was a normal dairy cow diet with no added oil. Then soybean oil at 2.5% was added as a source of omega-6, followed by 2.5% linseed oil as a source of omega-3. Both oils represented 2.5% of the total dry matter and replaced corn. These values ??were chosen because in previous studies of the group they improved the fatty acid profile of the milk without significantly changing the yield. Milk samples were then analyzed for fat, protein, lactose and total solids.
Research by the Saran Netto group published in 2016 showed that adding rapeseed oil to the diet of dairy cows also changes the fatty acid profile of their milk and makes it healthier (read more at: agencia.FAPESP.br/23371/).
Another study too funded by FAPESP experimented with supplements made from sunflower oil, organic selenium and vitamin E, improved animal health and milk yield and preservation, and showed that children who consumed the milk had elevated selenium and vitamin E levels in their blood.
demand
Historically, cow’s milk has been an important source of nutrients for human consumption. It is rich in proteins, calcium, magnesium, selenium and vitamin B12, among other things. However, over the past few decades, particularly in the US and Canada, demand has declined for a number of reasons, including health and dietary reasons. For example, the fat in milk can cause allergic reactions and usually contains saturated fat, which has been linked to weight gain and obesity. Therefore, much scientific research has been devoted to the adjustments needed to meet consumer demand for a healthier product.
With an annual production of 34 billion liters, Brazil ranks fifth among the world’s leading milk producers. Dairy products are one of the most important segments of the food industry. The annual milk consumption averages 170 liters per capita, which is below the average for industrialized countries (250-300 liters). UHT (Long Life) milk is the most widely consumed dairy product, but cheese sales have risen sharply in recent years.
The types of milk obtained from Saran Netto and his group are not yet available in Brazil, although research is more than complete. The main reason, he said, is logistical difficulties in distribution and industrial processing that have delayed commercialization.
“In many cases the same truck collects milk from multiple farms. This hinders the development of the product because we cannot mix normal milk and milk from cows with a certain diet. Likewise in industry: we need a separate production line for specialty milk, ”he said. “There is not yet enough consumer demand to guarantee sales volumes that would allow separate processing.” In the future, he hopes to be able to market milk with added omega-3 fatty acids and antioxidants.
The article “The inclusion of soy and linseed oils in the diet of dairy cows makes the fatty acid profile of milk for human consumption more nutritionally healthier” reads: journals.plos.org/plosone/article?id=10.1371/journal.pone.0246357.
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