Cow muscle cells can be engineered to produce beta-carotene, which the human body can then usually convert into vitamin A. This method, published in Metabolic Engineering, shows how cell-cultured meat might be able to surpass the nutritional profile of conventionally farmed meat.

Andrew Stout, lead author of the study and biomedical engineering PhD student at Tufts University, tells NutritionInsight that he expects other nutrients could also be produced similarly. 

“That is one of the things about this that I am the most excited about. Putting plant genes into mammalian cells is pretty untraveled scientific territory. There is a lot of space to explore other nutrients, flavor compounds and color compounds, for example.”

A double-duty effect
In this initial research stage, beta-carotene was used due to its role as an antioxidant.

“There is significant evidence for oxidative processes being involved in meat consumption’s connection to colorectal cancer. Therefore, the antioxidant nature of beta-carotene and the other carotenoids made them promising candidates for this proof-of-concept.”

Those same oxidative processes are major contributors to meat’s quality degradation over time, for example, off-flavors and color degradation. Therefore, beta-carotene offered a “double-duty” effect.

As the scientists have not produced enough cells to eat, it is unknown whether the taste would be altered. However, Stout flags that it is a possibility and notes that there is a color change in the cells. 

“They turn slightly yellow. They are usually white-ish and need to be colored anyway for a cultured meat product.”

Slashing carcinogenicity
According to Stout, this engineering technique allows nutritional benefits to be imparted directly onto a cultured meat product in a way that is likely infeasible through animal transgenics and conventional meat production.

Rather than simply mimicking meat currently found in the grocery store, cell-cultured meat products are capable of assuming different shapes, textures, nutritional profiles and bioactivities.
Another way this can be used is to reduce carcinogenicity. The researchers saw a reduction in lipid oxidation levels when a small pellet of these cells was cooked while they were expressing and producing beta-carotene. 

“Because that lipid oxidation is one of the key mechanistic proposals for red and processed meats’ link to diseases such as colorectal cancer, I think that there is a pretty compelling argument to be made that this could potentially reduce that risk,” says Stout. 

Golden rice comparisons
The scientists used the same carotenoid pathway exploited in golden rice, prompting comparisons between the two foodstuffs. Notably, issues ranging from farmer adoption to successful vitamin A conversion have prevented golden rice’s effective use. 

While golden rice was an inspiration to Stout, he stresses that different motives and considerations are at play. 

One notable difference is that golden rice was developed to address vitamin A deficiency, which is common in many regions facing poverty. 

“This work isn’t aimed at combating vitamin A deficiency, since – at least for the foreseeable future – cultured meat (and indeed, often conventional meat) isn’t an economical option for people facing vitamin A deficiency,” adds Stout.

However, he hopes that the cost can ultimately be driven down so that the product can be widely accessible. 

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