You are what you eat: ophthalmological manifestations of severe B12 deficiency

A strict vegetarian diet may be harmful: bilateral macular bleeding in vitamin B12 deficiency

A 35-year-old Indian male office worker presented with complaints of progressive weakness, fatigability, and diminished vision. The patient followed a strict vegetarian diet. Clinical examination revealed pallor. Fundoscopy revealed a bilateral macularbleed. Vitamin B12 deficiency was determined to be the cause based on the clinical and laboratory results. Three months later, he reported a near-normal vision in both eyes and a normal complete hemogram. The present clinical picture demonstrates an unusual facet of clinical feature in vitamin B12 deficiency, an event rarely encountered.

Linkage between a plant-based diet and age-related eye diseases: a systematic review and meta-analysis

CONTEXT

An increased risk of age-related eye disease has been observed in individuals lacking a balanced diet. Following a plant-based diet may result in nutritional insufficiencies and negatively affect health if an effort is not made to ensure the consumption of fortified foods or specific supplements.

OBJECTIVE

The purpose of this article is to characterize the relationship between plant-based diets and age-related ocular outcomes among adults.

DATA SOURCES

A comprehensive literature review was performed using the MEDLINE, Embase, Cochrane, and PubMed databases up until December 19, 2021.

STUDY SELECTION

Studies that focused on observed visual changes due to a reduced intake of animal products and that included a minimum of 50 eyes were eligible for inclusion.

DATA EXTRACTION

Two levels of screening, quality assessment, and data extraction were conducted by 2 reviewers independently. The 21 studies identified from 814 unique studies progressed to data extraction and 15 were included in the quantitative analysis using STATA 15.0 fixed-effect and random-effect models computed on the basis of heterogeneity.

RESULTS

The 15 (n = 51 695 participants) assessed the impact of fish consumption, 8 studies (n = 28 753 participants) analyzed the effect of red meat intake, and 3 studies (n = 7723 participants) assessed the impact of omission of skim milk, poultry, and non-meat animal products and the presence of disease incidence as indicated by age-related macular degeneration or cataract development. Meta-analysis indicated regular consumption of fish (odds ratio [OR], 0.70; 95%CI, 0.62-0.79) and skim milk, poultry, and non-meat animal products (OR, 0.70; 95%CI, 0.61-0.79) reduced the risk of age-related eye disease development among adults. Consumption of red meat (OR, 1.41; 95%CI, 1.07-1.86) may increase the risk of age-related eye disease development.

CONCLUSION

A pescatarian diet is associated with the most favorable visual outcomes among adults, whereas consumption of red meat negatively affects ocular health. Results suggest a need for more initiatives promoting a healthy and balanced diet.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021269925.

The clinical presentation of cobalamin-related disorders: From acquired deficiencies to inborn errors of absorption and intracellular pathways

This review gives an overview of clinical characteristics, treatment and outcome of nutritional and acquired cobalamin (Cbl; synonym: vitamin B12) deficiencies, inborn errors of Cbl absorption and intracellular trafficking, as well as methylenetetrahydrofolate dehydrogenase (MTHFD1) and methylene tetrahydrofolate reductase (MTHFR) deficiencies, which impair Cbl-dependent remethylation. Acquired and inborn Cbl-related disorders and MTHFR deficiency cause multisystem, often severe disease. Failure to thrive, neurocognitive or psychiatric symptoms, eye disease, bone marrow alterations, microangiopathy and thromboembolic events are characteristic. The recently identified MTHFD1 defect additionally presents with severe immune deficiency. Deficient Cbl-dependent enzymes cause reduced methylation capacity and metabolite toxicity. Further net-effects of perturbed Cbl function or reduced Cbl supply causing oxidative stress, altered cytokine regulation or immune functions are discussed.