Nutrition factor 1 scores (vitamin C, quercetin, β-carotene and β-cryptoxanthin)
Nutrition factor 2 scores (vitamin E, lysine, DHA omega−3 and LA omega−6)
Nutrition factor 3 scores (epigallocatechin 3-gallate)
Various foods have each of these, except the last one, which is EGCG that primarily comes from green tea, followed by white tea, and basically nothing else.
DHA Omega-3 comes from salmon and other ocean-based fatty fish. Omega-6 comes from some plant fat and animal fat.
I will leave the rest as an exercise for others to add to, but there are plenty of websites that tell you foods high in each.
4.3. Associations between nutrition factor scores and longitudinal QSM
Our results offer evidence that dietary factors may play a role in moderating the accumulation of brain iron. We observed that nutrients typically found in fruits and vegetables (factor 1) may help reduce iron accumulation in the basal ganglia, especially within the pallidum. This contrasts with nutrients categorized under factors 2 and 3—primarily antioxidants, iron chelators, and polyunsaturated fatty acids—which demonstrated a more pronounced effect in cortical areas, including frontal cortex, and the hippocampus.
Interestingly, factor 2 nutrients exhibited the most widespread associations, with lower iron accumulation in seven cortical regions. Factor 1, while showing the strongest negative association with iron accumulation, had its impact confined mostly to the right pallidum. Factor 3 nutrients, had a more limited and weaker association with brain iron levels, affecting only two cortical regions and with substantially lesser effect sizes compared to factors 1 and 2.
Our finding that higher dietary intake of antioxidants, polyunsaturated fatty acids, and iron chelators moderates age-related brain iron accumulation, align with the background literature on the importance of exogenous antioxidants in aging. This literature indicates that oxidative stress caused by excess non-heme iron impairs mitochondrial function, which prompts the additional release of iron from ferritin as the cells attempt to restore normal mitochondrial operation and maintain iron balance (Ward et al., 2014). This vicious cycle is particularly important in aging where endogenous defense mechanisms, specifically ones that depend on nonenzymatic antioxidants (e.g., glutathione, melatonin, vitamins A, C and E and flavonoids; Jovanovic, 2014), become less effective (Harman, 1998; Jovanovic, 2014; Molinari et al., 2019). Therefore, increased intake of exogenous antioxidants (such as vitamin E and lysine) could become more important at reducing brain iron accumulation with increasing age. PUFAs such as omega-3 fatty acids also have antioxidant properties and are also linked to the prevention of age-related ferroptosis, a cell death mechanism triggered by iron-induced oxidative stress (Ogłuszka et al., 2020). Lastly, iron chelators can enter cells, bind with free iron and effectively reduce its concentration (Entezari et al., 2022).