EAT planetary diet improves nutritional quality of teen diets

New analysis of data from the large multi-centre HELENA study demonstrates that greater adherence to the EAT Lancet Planetary Health Diet leads to healthier dietary patterns and improved nutritional quality and status.(1) The primary objective of the study was to validate the Planetary Health Diet Index (PHDI) in European teenagers by comparing its score to the Mediterranean Diet Score (MDS), as well as dietary consumption data and food consumption biomarkers.

Data collection

The data was collected from participants of the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study, which recruits teenagers aged between 12.5 and 17.5 years from 10 European countries. Although the PHDI has been validated in adults, its validation in teenagers has not been previously established.

Dietary information

Dietary information was collected from 2 non-consecutive 24-hour diet recall. Under-reporters were excluded to increase the accuracy of the data.

The Planetary Health Diet Index

The PHDI assesses four food components:

• 5 Adequacy food components: nuts and peanuts, legumes, whole grains, fruits, and vegetables.

• 5 Optimum food components: eggs, fish and seafood, tubers and potatoes, dairy, and vegetable oil.

• 2 Ratio food components: dark green vegetables and orange/red vegetables in relation to total vegetable intake.

• 4 Moderation food components: red meat, poultry and substitutes, animal fat, and added sugars.

The PHDI score ranges from 0 to 150, with higher scores indicating greater adherence to the EAT Planetary Health Diet.

The Mediterranean Diet Score

The Mediterranean Diet Score (MDS), which ranges from 0 to 9, is based on nine components and nutrients: vegetables, fruits, nuts, cereals and tubers, legumes, fish, dairy, and the unsaturated to saturated fat ratio. Each component is compared to sex-specific median benchmarks.

A score of ≤4 indicates low adherence, while a score of ≥9 indicates high adherence to the Mediterranean diet.

Results

In this study, a total of 1,804 teenagers' food records were evaluated for nutritional values and compared to their PHDI and MDS scores.

PHDI scores

The results indicate that the mean PHDI score was relatively low at 44.3 (range 43.7-44.9), suggesting low adherence to the EAT Planetary Health Diet recommendations. This average score corresponds to approximately 29% of the maximum PHDI score and is similar to the findings of a 2017 study conducted on Brazilian teenagers.

Analysing the individual food components, the highest PHDI scores were achieved for fruit and animal fat recommendations, followed by whole grain and vegetable intakes. The lowest adherence was observed for recommendations regarding red meat, eggs, fish, nuts/peanuts, and tubers.

Interestingly, younger adolescents (aged 12 to <14 years) exhibited higher PHDI scores compared to older teenagers (≥16 years). Furthermore, the education level of the parents significantly influenced the teenagers' PHDI scores, with higher scores observed among teenagers whose parents had higher education levels.

There was a positive correlation between the MDS score and the PHDI score.

Higher PHDI scores were associated with improved positive nutrient intakes and status. Each one-point increase in PHDI scores led to small but significant reductions in animal protein, total and saturated fat, and cholesterol intake, as well as a significant increase in carbohydrate, fibre, and vegetable protein consumption. However, it is worth noting that these changes are likely to be of minimal physiological significance.

PHDI associated with better micronutrient status

Micronutrient intakes increased with each unit increase in PHDI score, with most vitamins and minerals showing a positive correlation. It is not surprising that there was no significance found for vitamin D, as only a few foods are good sources of it. Interestingly, there was also no significance found for vitamin B12 or retinol, which would be expected in diets higher in plant foods and lower in animal foods.

Similarly, PHDI scores showed a positive correlation with most minerals, except for haem iron, which significantly reduced by 0.06mg. Despite the statistical significance, it is unlikely to be of physiological significance as this represents just 0.5% of the EAR for teenagers.

Higher PHDI scores were associated with increased plasma levels of beta-carotene, vitamin C, folate, and ferritin, as well as lower levels of trans fats.

Conclusion

In summary, this study validates the use of PHDI in assessing the nutritional quality of teenage diets. Moreover, it highlights the nutritional adequacy of the EAT Planetary Health Diet for a population group with significantly higher micronutrient demands compared to adults. This should reassure professionals that healthy and sustainable dietary patterns do not compromise micronutrient status and have the potential to improve micronutrient status.

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