Ready-to-use therapeutic foods (RUTFs) form the basis of the nutritional management of uncomplicated severe acute malnutrition (SAM), administered to millions of children worldwide every year [1]. RUTFs are intended as the sole food for several weeks during the rapid catch-up growth phase of treatment. Therefore, their nutritional composition must be complete and appropriate to support all aspects of growth and development.
The conventional recipe for RUTFs leads to a high energy density food made with a peanut base with added powdered milk, sugar, and fat, with 45% to 60% of the energy derived from fat. Commodity peanuts and predominant vegetable oils from which RUTFs are commonly made contain a high omega-6 linoleic acid (LA) content relative to essential fatty acid requirements and negligible omega-3 alpha-linolenic acid (ALA) as sources of omega-6 and omega-3 fatty acids, respectively. LA and ALA are the dominant forms of the two polyunsaturated fatty acid (PUFA) families acquired from plant foods, particularly vegetable oils. Their primary function is to serve as substrates for endogenous metabolism, which converts them to long chain PUFAs (LC-PUFA). Best known among these are omega-6 arachidonic acid (AA) and omega-3 eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Omega-6 LA and AA are seldom, if ever, limiting in the diet of otherwise well-nourished free living humans, while EPA and particularly DHA levels are known to be limiting from human studies that show DHA supplements improve status and function. Neural tissue membranes are particularly rich in DHA, accumulating perinatally, and both EPA and DHA have roles in immune function and modulation of inflammation. They can be consumed through foods of marine origin (e.g., fish, shellfish), but these are often expensive and/or prone to rapid spoilage, a property incompatible with the RUTF requirement of a long shelf-life under ambient environmental conditions.
Scores of studies show that developing animals, deprived of omega-3 fatty acids using peanut and similar omega-3 fatty acid-deficient oils during development, grow normally but have functional deficits. These include poor maze navigation performance, aggression, poor impulse control, and poor balance, to name a few, as well as a myriad of biochemical deficits [2]. This is due, in part, to replacement of the major structural fatty acid in the brain, omega-3 DHA, by an abnormal amount of the analogous omega-6 fatty acid docosapentaenoic acid, leading to neurocognitive deficits [2]. RUTFs do have marginal amounts of omega-3 ALA delivered by including an oil such as soybean or rapeseed oil with small amounts of ALA; normally, such oils contain more omega-6 LA and thus result in an RUTF which is out of balance with respect to the child’s sole nutritional source of the two essential fatty acid families. Beyond this, effects of the tissue omega-6-omega-3 balance on inflammation and blood clotting are well recognized, and recent work has implicated them in pain sensitivity, which likely has repercussions in psychological well-being [3,4].
While RUTFs are recognized as the major contributor to children’s recovery from SAM, increasing recognition of support of normal development has led to more careful consideration of oil composition.