EAT-Lancet Commission’s planetary health diet lacking in micronutrients, flag experts

07 Mar 2023 --- The plant-based focused planetary health diet has significant dietary gaps in six essential micronutrients and contains large amounts of phytate – an anti-nutrient found in many plants. Researchers are now saying that to meet these nutrient shortfalls, the diet should be amended to include an increased proportion of animal-source foods and a reduction of foods high in phytate.

Women of reproductive age (15 to 49) were impacted even more severely due to their increased need for the micronutrient iron during menstruation, as the diet only provides 55% of women’s intake recommendations.

“The planetary health diet is likely to help protect against noncommunicable diseases, which are the leading causes of death and disease worldwide, and to do so sustainably,” says Dr. Ty Beal, research advisor at the Global Alliance for Improved Nutrition (GAIN).

“The challenge in providing enough micronutrients is doing so sustainably. It is not clear exactly how much animal source food, and which types, could be sustainably produced worldwide: experts have different perspectives,” states Dr. Jessica Fanzo, professor of food policy at Johns Hopkins University and co-author of the study. 

The study shows that the micronutrient deficiencies are even worse for women.“But there is a limit and there will inevitably be trade-offs to grapple with, between human health and environmental sustainability,” 

Diet worse for women
One major problem the study, published in The Lancet Planetary Health, found with the proposed planetary health diet is the high amount of phytate the diet contains. Phytate, or phytic acid, is the principal storage form of phosphorus in many plant tissues – mainly in seeds and bran. 

Phytate can form complexes with proteins and some metals and reduce their bioavailability in the gastrointestinal tract. Some of the nutrients it impacts are zinc, iron and calcium, which are three of the six micronutrients that are already lacking in the planetary health diet. The other three are folate, vitamin A and vitamin B12.

Recommended iron intakes in the US for women aged 19–50 years are more than double the recommended iron intakes for men of the same age due to increased need. Moreover, folate has been shown to be the easiest way to prevent neural tube defects in developing babies. 

Additionally, women are also in greater need of the minerals calcium and zinc as they reach menopausal age to help promote bone health and defend against osteoporosis. 

“These new findings on shortfalls in essential vitamins and minerals are concerning because deficiencies in these ‘micronutrients’ can lead to severe and lasting effects, including compromised immune systems and increased risk for infections; hindered child growth, development, and school performance; and decreased work productivity; all of which ultimately limit human potential,” stresses Beal.

Minimally processed and nutrient-dense
The researchers recommend that global diets maintain a moderate amount of minimally processed nutrient dense animal-based foods such as shellfish, fish, eggs, and beef to help ensure nutrient adequacy.

The study reveals that for some nutrients, such as retinol from vitamin A, animal-based sources were 12 times more bioavailable than plant sources due to the low content and high phytate amounts in many plant-based sources.

Though the researchers state that some of these deficiencies could be made up through supplementation, they also acknowledge that supplementation in the amounts needed is not available to all people in all places and might still be inadequate, especially for women.

“Future efforts to propose healthy and sustainable diets must ensure micronutrient adequacy, tailor recommendations according to the local context, equitably involve local stakeholders impacted by any changes, and be transparent about trade-offs,” Dr. Mduduzi Mbuya, director of knowledge leadership at GAIN, concludes. 

“Preserving human health and protecting our planet are more important now than ever. All of society must rise to the challenge, now, to address these integrally linked and equally important challenges.”

By William Bradford Nichols