Researchers at Rutgers and Tufts universities published findings Tuesday in the Journal of Parenteral and Enteral Nutrition (JPEN), which states that concerns on soybean-based emulsions causing higher rate of infections in infants receiving parenteral nutrition may be unwarranted. According to a press release, the article also says that combination lipid emulsions based on triglyceride oil, fish oil, or olive oil, which were developed as an alternative, do not possess any significant benefits over soybean-based emulsions.

This research is of great significance, considering that parenteral nutrition with lipid emulsions can be life-saving for infants who are unable to digest and absorb milk feeds. Such infants are generally premature babies or suffer from intestinal failure due to congenital defects or other issues. Lack of nutrition might lead to reduced brain growth and neurological issues.  But intravenous lipid emulsions can address these issues by providing the essential fatty acids and energy needed for development in the early days and months of life.

Soybean oil was first used as a lipid emulsion in the 1960s. The emulsions, composed of long chain fatty acids, phytosterols, high proportion of omega-6 fatty acids, and low alpha-tocopherol levels was developed by a group of Swedish researchers. While most pediatric patients showed good tolerance to it some researchers believed that the high content of omega-6 fatty acids was responsible for compromising immunity and promoting liver damage. High levels of omega-6 fatty acids are also known to cause inflammatory and autoimmune diseases.

To address these issues, combination lipid emulsions based on triglyceride oil, fish oil, or olive oil were developed. These emulsions provide the essential fatty acids as they contain medium chain oils and at the same time contain smaller concentration of omega-6 fatty acids, and lower levels of phytosterols. Recent studies  have also shown that olive oil-based emulsions have higher vitamin E content compared to soy-based emulsions.

Previous research has shown a connection between lipid emulsions and triglyceride levels. Lipid emulsions affect triglyceride levels, which consequently affect levels of bilirubin levels used as indicators of liver damage and nutritional status. These studies showed that patients treated with fish oil-based emulsions showed reduced triglyceride levels resulting in better liver function compared to those given soy-based emulsions.

But the new research published in JPEN found the evidence pointing to these comparisons as being inadequate. A systematic review of these studies did not provide sufficient information on the benefits of combination lipid emulsions over soy-based emulsions on bilirubin levels, triglyceride levels, or infection incidence in infants.

Even though the study does not show significant health benefit differences between the two types of lipid emulsions, it does suggest that combination lipid emulsions are a safe alternative to soybean-based emulsions.

The researchers also recommend in-depth analysis and larger randomized controlled trials to determine if one type of emulsion is superior to the other.

Source: Journal of Parenteral and Enteral Nutrition. 2014.