Refined carbohydrate‐rich diet is associated with long‐term risk of dementia and Alzheimer's disease in apolipoprotein E ε4 allele carriers

Abstract

INTRODUCTION: In animal models, refined carbohydrates (RF) worsen Alzheimer's disease (AD). However, the long-term effects of high RF intake on the risk of dementia and AD are poorly described in epidemiological studies. Moreover, the interaction between RF and apolipoprotein E ε4 allele (APOE-ε4) is unknown. Our study investigated whether RF-rich diets are associated with the risk of dementia and AD. METHODS: The glycemic load was quantified in 2,777 elderly participants from the French Three-City Study to estimate RF intake. Then, the association between glycemic load and risk of dementia and AD, and the interaction with APOE-ε4 over a 12-year period were assessed using proportional hazards models. 1 1 2 RESULTS: After adjustment for potential confounders, high afternoon-snack glycemic load was associated with increased dementia and AD risk in APOE-ε4 carriers (HR = 1.27 [1.03-1.56]). DISCUSSION: This study highlights that RF-rich diets are a risk factor for dementia and AD in APOE-ε4 carriers.

High Glycemic Load Is Associated with Cognitive Decline in Apolipoprotein E ε4 Allele Carriers

“…As we previously observed an interaction between GL and APOE4 only for the afternoon snack (snack between lunch and dinner) [16], we hypothesized that, in APOE4 carriers, the afternoon -snack GL might be associated with a greater decline in cognitive performance over time.…”

“…Thus, the baseline of the present analyses was the 2-year follow-up visit for Bordeaux and the 4-year follow-up visit for Montpellier. This subsample has been previously described [16]. Participants with prevalent dementia at the baseline of the present analyses were excluded (n = 174).…”

“…Dietary data were collected using the 148-item FFQ. The FFQ was divided into breakfast, lunch, dinner, and snacks between meals, and was described elsewhere [16]. For each FFQ item (i.e., food/beverage categories), the GL was calculated as the product of the glycemic index (GI) and the amount of available carbohydrates in a standard serving size, divided by 100 [22].…”

“…Smoking status (never, past, or current) was also investigated. The Mediterranean-like diet score was used to control for diet quality, as previously described [16]. Physical activity was defined as none, or low/regular [38].…”

“…In this context, our recent work highlighted that high-GL diet, which reflects an elevated intake of refined carbohydrates, increases the risk of dementia in APOE4 carriers [16]. Yet, the impact of the diet GL on long-term cognitive performance, especially in the different cognitive domains (verbal fluency, visual memory, attention, visual motor processing speed, episodic memory), is poorly understood.…”