A pregnancy nutrition program built around whole foods and local produce appears to have helped babies’ brains grow before birth. Researchers at Washington University in St Louis led the work. Their results were published in the Proceedings of the National Academy of Sciences. Funding came from the Children’s Discovery Institute, a partnership involving St Louis Children’s Hospital, its foundation and WashU Medicine.
The trial was named Mikhuna, a word that means “nourish” in Kichwa, an Indigenous language of Ecuador. It enrolled 215 healthy pregnant women from two low-income communities on the edge of Quito. Of those, 111 joined the intervention group, and 104 stayed in a control group with normal prenatal care. Starting at roughly 12 weeks of pregnancy and continuing until delivery, the intervention group got food delivered every week. Each delivery included eggs, fish, fruits and vegetables. The women also got advice on eating a wider range of foods and cutting back on ultraprocessed products.
The design came from an unusual idea. Instead of handing out pills or fortified powders, the team looked at what people ate across human evolution and then translated those principles into foods available in Ecuador. The team collected information on the mothers’ diets, their health and their economic circumstances during pregnancy, plus a follow-up two weeks after birth.
By the final months of pregnancy, women in the Mikhuna group were eating a noticeably more varied diet. Ultrasound scans also showed more brain growth in their babies. The clearest effect appeared in a deep structure called the gangliothalamic ovoid, or GTO. That region helps with movement, with processing what the senses take in, and with thinking and reasoning.
The study grew out of decades of work by Lora L. Iannotti, a distinguished professor at the WashU Bursky School of Public Health. She directs the E3 Nutrition Lab, which studies nutrition through equity, environment and evolution. Her focus is the stretch from conception through a child’s second birthday.
That window matters enormously. Chronic undernutrition in early life causes stunting, which slows growth and development and affects 22.5% of children worldwide. Stunted children face higher risks of illness and death, tend to complete less schooling, and earn less as adults. The effects can pass down to the next generation. Poor diets can also cause “hidden hunger”, where a child eats enough calories but still lacks key nutrients.
“The consequences of being undernourished in that period can be irreparable,” Iannotti said. She added that children whose nutrition is damaged during the first 1,000 days will likely never reach their full genetic potential.
Ecuador shows how tangled these problems have become. Stunting rates stay stubbornly high while obesity climbs, and nutrient shortfalls remain common. More than ten years ago, researchers found over 13% of Ecuadorian households dealing with some mix of stunting, excess weight, anaemia and zinc deficiency. Iron and zinc are known to matter for a growing brain, but how a mother’s overall diet shapes that brain has been far less clear.
Many nutrition programs in poor areas rely on single nutrients or supplements. Popular templates like the Mediterranean diet often call for expensive, unfamiliar or simply unavailable foods. Mikhuna went another way.
The evolutionary starting point is straightforward. Ancient diets covered a broader range of foods than modern ones, which lean heavily on starchy staples and packaged products. Gatherer-hunter-fisher diets, spanning roughly 2.5 million years until farming arrived about 10,000 years ago, differed by region. Broadly, they supplied more protein and fat from animals, fewer carbohydrates, and more fibre and micronutrients from plants.
The Mikhuna basket put those ideas into practice. Each week brought eight eggs and 500 grams of fish, plus a changing selection of fruits, vegetables, herbs and spices. Native crops such as naranjilla and mora, an Andean blackberry, were included. The produce came from farms using agroecological methods, which was meant to support local food systems.
The diet results were clear. At the end, 74.5% of Mikhuna women met the minimum standard for a varied diet, versus 55.8% of controls. They reported eating about 14 different foods a day, compared with nine. Rice and ultraprocessed foods stayed common in both groups.
For the imaging, the team used portable ultrasound at 21 and 35 weeks, looking at deep structures that routine scans skip. Between those two points, GTO growth was 0.15 centimetres greater in the Mikhuna group. That difference held up after statistical adjustment.
Two other results did not survive adjustment: 0.19 centimetres more growth in the corpus callosum, the brain’s largest white-matter tract, and 0.10 centimetres less femur growth. Dairy intake and supplement use were similar, so neither explains the bone finding. Newborn size was the same in both groups. The authors emphasise the necessity of further research.
Jennifer Nicholas, a paediatric radiologist at Cincinnati Children’s, helped build the imaging method, with input from WashU Medicine’s Manu S. Goyal and Marcus E. Raichle. Portable ultrasound is cheap and noninvasive, which makes it practical for low-resource settings.
“We’re looking at what I would consider to be the biological mechanism, or the pathway,” Iannotti said. What matters most, she added, is how the child actually develops.
Ecuador’s Ministry of Health was a partner from the start, and the trial ran inside ministry clinics. An earlier Iannotti trial gave infants one egg daily from six months of age and cut stunting by 47%, prompting the ministry to revise national guidance. Mikhuna extends this approach to pregnancy, emphasising the importance of a whole dietary pattern rather than focusing on a single food. The team is now working toward a national pregnancy nutrition program with government and private partners.
