Does plant-based necessarily mean healthy and sustainable?

Do vegetarian diets provide adequate nutrient intake during complementary feeding?

According to the World Health Organization (WHO), a healthy diet rich in fruit and vegetables could prevent approximately one third of cardiovascular diseases (World Cancer Fund Research, 2017) and could be a protective factor against mental disorders (Rahe, 2014). A healthy diet includes a varied, balanced intake of foods, with all food groups.

A healthy diet should not exclude any food group ; needs to provide on its own, without any supplements, all the macro-and micronutrients to fully satisfy, at any stage of infancy and childhood, all nutritional needs and to promote the best possible psychophysical development.
World Health Organization, 2018

Worldwide, the number of people adopting a vegetarian diet seems to increase (for example, from 0.2% to 3-7% in 40 years in the UK) (Philips, 2005). Consequently, since children tend to follow their family’s dietary pattern, parents consult more commonly the pediatrician for advice on how to provide their infants with a diet partially or totally free of animal foods. The first 1,000 days are particularly vulnerable from a metabolic and neurodevelopmental perspective (Schürmann, 2017).

Thus, a systematic review was conducted to assess the evidence for the impact of complementary vegetarian diets on health outcomes during the first 1,000 days.

Vegetarian diet leads to nutritional deficiencies in infants during the first 1 000 days

The effects of dietary deficiencies of individual nutrients have been extensively studied, particularly during complementary feeding. This period is crucial in the growth of infants as they are vulnerable to nutrient deficiencies and excesses (Lövblad, 1997).

While the quality of evidence is low, the case reports are all consistent in demonstrating severe
neurological outcomes and growth deficits in children on a vegan diet, due to low vitamin
B12 and vitamin D levels, such as anemia, stunting, brain abnormalities and demyelination (Lemoine, 2020; Lund, 2019; Lövblad, 1997).

During the first two years of life, excluding meat, fish and meat products from diets is mostly critical for vitamin B12 deficiency. Other nutrients may also be deficient such as calcium, iron, iodine, zinc, and selenium, essential amino acids, ω-3 LC-PUFAs (EPA and DHA) (Kristensen, 2015; Black, 2008; Algarin, 2013).

However, few studies evaluated the long-term effects of early deficiencies from vegetarian diets and potential irreversible effects (motor or cognitive delays, possible links to psychopathological disorders, etc.). For ethical reasons, no interventional study investigated the impact of non- supplemented vegetarian/vegan diets on the physical and neurocognitive development of children

Vegetarian diets have no protective effect on noncommunicable diseases and obesity in the early years of life

Studies demonstrating the effect of vegetarian diets on noncommunicable diseases prevention are heavily biased. In fact, these studies are mostly conducted on adults which therefore makes the translation of the results on pediatric population difficult (SIPPS, 2017).

In adults, vegetarian diets were found to be effective on some outcomes, such as reductions in serum cholesterol and LDL, for oxidative stress and body fat tissue. However, in the overall evaluation of these results, it should be taken into account that vegetarians have an overall healthier lifestyle with fewer risk factors (no alcohol consumption, cigarette, sedentary lifestyle, etc.) (very low quality of evidence). However, to date, it seems that there is no specific study on the impact of the vegetarian diet during complementary feeding on these parameters. (SIPPS, 2017).

In addition, a recent meta-analysis found no protective effect of vegetarian diets on noncommunicable diseases in the early years of life, at least at a two-year follow-up, although vegetarian diets are often recommended to prevent overweight and obesity (Weder, 2019).

Concerning the occurrence of type 2 diabetes and hypertension later in life, no study was identified on the influence of adopting a vegetarian diet during complementary feeding.

In conclusion, vegetarian and vegan diets are inadequate for the correct neuro-psycho-motor development of children because of potentially serious side effects caused by vitamin and micronutrient deficiencies. In particular, numerous clinical cases showed the damage, sometimes irreversible, that can cause a deficiency in vitamin B12, DHA and iron to the nervous system. Therefore, they cannot be recommended during the period of complementary feeding.

Moreover, the effects of vegetarian diets on diseases prevention are still largely undocumented, particularly when adopted in the early years of life. According to current available evidence, they have no protective effects on noncommunicable diseases, cardiovascular diseases, and obesity.

What is a vegetarian diet?
    Vegetarian diets can be classified as:

  • Pescetarian (no meat)
  • Lacto-ovo vegetarian (no meat, fish, mollusks)
  • Lacto-vegetarian (no meat, fish, mollusks, crustaceans,eggs)
  • Ovo-vegetarian (no meat, fish, mollusks, crustaceans, milk and dairy products)
  • Vegan (excluding all foods of animal origin, including : eggs, honey, milk and dairy products propolis royal jelly)

    These forms can have specific subtypes, such as : rax food diet, fruitarian diet, macrobiotic diet, etc.

Based on: Simeone G, et al. Do Vegetarian Diets Provide Adequate Nutrient Intake during Complementary Feeding? A Systematic Review. Nutrients. 2022 Aug 31;14(17):3591.

Key messages
  • Based on current evidence, vegetarian and vegan diets during the complementary feeding period have not been shown to be safe.
  • The risk of critical micronutrient deficiencies or insufficiencies and growth retardation is high: they may result in significantly different outcomes in neuropsychological development and growth when compared with a healthy omnivorous diet such as the Mediterranean Diet.
  • Vegetarian and vegan diets during complementary feeding period have no preventive effects on noncommunicable and cardiovascular diseases
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