Brazilian researchers develop healthier beef

The meat, shown here prepared for analysis, was enriched with vitamin E, canola oil and selenium and contains less cholesterol.

By Elton Alisson

Agência FAPESP – In addition to different types of cuts, beef aficionados may soon be able to find healthier varieties of the product in the country’s butchers and supermarkets. Beef has long been considered the antithesis of a healthy diet because of its high saturated fatty acid and cholesterol contents.

Researchers from the School of Zootechny and Food Engineering (FZEA) at the Universidade de São Paulo (USP) Pirassunungra campus developed beef enriched with vitamin E, selenium and canola oil and less cholesterol. 

The results of the FAPESP-funded research that led to the development of the product were presented at international science and technology conferences on animal and meat production that were held over the last few months in France, Turkey and Cuba. 

“We supplemented Nelore bull rations with high levels of organic selenium during a three-month fattening period, and we found that in addition to increasing the quantity of selenium in the blood of these animals, the level of this mineral in the meat produced was almost six-times greater than that found in beef that did not have supplemented rations,” said Marcus Antonio Zanetti, professor at FZEA and coordinator of the project.

“The cholesterol level in the blood and meat of the animals that were given high-selenium feed was also reduced significantly,” he affirmed.

According to Zanetti, the laboratory and statistical analyses of the blood and meat samples indicated that the increased quantity of selenium in the diet caused alterations in the levels of oxidized glutathione (GSSG) and reduced glutathione (GSH). These enzymes inhibit the action of the enzyme responsible for cholesterol synthesis: HMG-CoA reductase.

The mineral causes an increase in the quantity of GSSG and a decrease in GSH, causing a reduction in cholesterol owing to the action of HMG-CoA reductase, stated the researcher. 

According to Zanetti, one of the possible explanations for these changes in the cholesterol level in the blood and meat of the animals that were given selenium supplements is that the mineral is part of glutathione peroxidase (GPx), an enzyme that is very similar to HMG-CoA reductase.

Upon contact, selenium transforms GSH into GSSG, reducing the quantity of substrates for HMG-CoA reductase.

“In another FAPESP-funded study, we had already proven that copper has the capacity to reduce cholesterol levels in the blood and meat of bovine cattle,” explained Zanetti. “The mechanism through which copper does this is different. It alters the metabolism in the animal’s rumen.”

Human analysis

To evaluate whether ingesting the meat of the animals that were given rations supplemented with selenium also caused an increase in the availability of the mineral and a reduction in cholesterol of humans, researchers conducted a study with elderly people in an assisted living facility in Leme, São Paulo State.

The study was conducted with the authorization of both the institution and the legal guardians of the elderly participants.

According to the researcher, the group of elderly individuals was chosen to participate in the study because they have lower immunity and anemia in general owing to iron and protein deficiencies. 

“It was very challenging to conduct a study with elderly people because during the monitoring period, some of the participants were transferred to hospitals and other assisted living institutions, which reduced the number in the control group,” explained Zanetti. 

For periods of up to 90 days, vitamin- and selenium-enriched meat was included in the meals of 80 elderly people and was presented in different ways (e.g., as ground meat, meatballs or stewed beef).

Nutritionists hired especially for the project were responsible for controlling and monitoring the diets containing selenium-enriched beef that were provided to the elderly individuals.

An analysis of blood samples of this elderly population indicated that there was also an increase in selenium in the blood plasma after 45 days of consuming the meat. 

“The analysis of the cholesterol levels in the blood samples of elderly people who consumed the meat has not yet been concluded,” explained Zanetti. “However, we can already see that there has been an increase in the availability of vitamin E and selenium in the blood of those who consumed the meat for more than 45 days.”

According to Zanetti, selenium is considered to be an important antioxidant mineral because it impedes the formation of free radicals, helps to combat infections and increases immunity.

However, studies conducted at USP’s School of Pharmaceutical Sciences proved that with the exception of the population in the North region, where there is high consumption of selenium-rich Brazil nuts, the diet of Brazilians is largely deficient in this mineral because of its low levels in the majority of the country’s soil.

The development of products such as selenium-enriched beef could help to improve the diet of the Brazilian population, stated the researcher. 

“Daily consumption of 200 grams of selenium-enriched meat can provide the recommended daily consumption of the mineral [50 micrograms],” he added. 

“By consuming 100 grams of the meat, an adult person reaches 50% of his/her daily mineral needs,” he affirmed.

In a previous study, also conducted with FAPESP funding, researchers added sunflower, selenium and vitamin E supplements to the rations to increase the availability of the mineral in the milk produced by the animals.

The enriched milk was given to children from 1st through 4th grade who studied full-time at Escola Professora Stela Stefanini Bacci in Casa Branca, São Paulo. 

The results of the analysis showed that in addition to offering health benefits for cows and increasing milk production, enriched feed improved product conservation and increased the selenium and vitamin E levels in the blood of children who drank it. 

“These two studies – enrichment of bovine milk and meat through feed supplements – are the first of their kind worldwide because they associate zootechny and animal nutrition with human health,” affirmed Zanetti.

Increased shelf life

According to the researcher, vitamin E was combined with selenium in the supplementation of beef rations because of their complementary antioxidant effects. 

In addition to reducing cholesterol, the addition of the two antioxidant compounds to bovine rations also reduced the oxidation of the meat’s fat, according to the results of oxidation analyses using a method known as TBARs.

The results of the study were presented in November at the 23rd Meeting of the Latin American Association of Animal Production (ALPA), held in Cuba.

“By reducing the product’s oxidation time, selenium and vitamin E in the bovine rations could contribute to increasing the meat’s shelf life,” he explained.

“Less oxidized meat, with less fat, also has better flavor,” he added.

The addition of canola oil to bovine rations with selenium and vitamin E, on the other hand, aims to improve the lipid profile of the meat by increasing the quantity of saturated fatty acids, which are the most harmful to human health.

“Utilizing canola oil with the two antioxidant compounds – selenium and vitamin E – prevents the increased fat from altering the product’s flavor,” explained Zanetti.

“The lipid profile of the meat is being analyzed so that we will know whether enriching animal rations with canola oil changes the fat levels in the meat,” commented Zanetti.

According to the researcher’s calculations, supplementation of the meat with selenium alone would increase the cost of the meat by R$ 0.20 per kilo. 

“We utilized the maximum dosage of selenium in the animal rations. The idea, however, is to conduct new studies with smaller doses. This would reduce the cost of supplementation even further,” he estimates.

“In developed countries, there is this type of product that is enriched naturally, and the consumer pays for the health benefits it offers,” he explained.