Flaxseed Supplementation in Prediabetic Adults (LINAPRED) (LINAPRED)

Prediabetes is the term used to describe the condition where blood glucose level is higher than normal but lower than the diagnosis criteria of type 2 diabetes mellitus (T2DM). This condition confers a high risk for the development of T2DM and other diseases. Prediabetes could be reversible with lifestyle modifications, which include medical-nutrition therapy. Within these modifications, a healthy diet high in fiber and sources of alpha-linolenic acid is recommended. Flaxseed is a seed that is considered a functional food because it can provide health benefits due to its high content of fiber, alpha-linolenic acid, and lignans, these components could improve glycemic control in prediabetes patients by different mechanisms. The purpose of this study is to assess the effect of flaxseed on glycemic control in prediabetic adults.

Prediabetes is a condition that increases the risk of T2DM and other diseases, its prevalence increases year after year despite being a reversible condition through lifestyle changes, diet, and medication. Therefore, it is important to find new strategies that, together with the known treatments, help to improve glycemic control in people with prediabetes and thus their risk of developing TDM2. Among these strategies may be the consumption of flaxseed, one of the main sources of alpha-linolenic acid (ALA), an omega-3 fatty acid, lignans, and fiber. This open-label randomized clinical trial will include, prior informed consent, 96 men and women with prediabetes, subjects will be allocated in two groups, the intervention group or the control group. The intervention group will receive 30 g per day of ground flaxseed dissolved in water, (15 g in the morning and 15 g in the night), they will also be provided with a dietary plan. The Control group will not receive any supplementation, only a dietary plan controlled in alpha-linolenic acid. The intervention will last 12 weeks; during this time, all patients will be scheduled every 2 weeks for follow-up visits. During the follow-up visits, subjects will be evaluated for changes in gastrointestinal symptoms, and adherence to supplementation, which will be assessed by a daily record, and the return of empty or unopened bags of flaxseed. Every month, all subjects will undergo anthropometric, clinical, dietary, and biochemical evaluations that include measurements of body weight, body composition, waist, and hip circumferences, blood pressure, physical activity, quality of food intake, dietary intake, fasting plasma glucose, hemoglobin A1C, insulin, LDL-C, HDL-C, triglycerides, and total cholesterol; an oral glucose tolerance test will be performed at baseline and the end of the study to each subject. At the end of the study, the obtained information will be shared with the scientific community to provide a possible food-based strategy for prediabetic adults in addition to the already known prediabetes treatment. All participants of the study will be beneficiated with free nutritional, anthropometric, and biochemical assessments.

Flax, Flaxseed, Linseed, Linum usitatissimum, Glycemic Control, Glycated Hemoglobin, Hemoglobin A1c, Glucose Tolerance Test, Blood glucose, Insulin resistance

A total of 30 g of ground flaxseed per day divided into two portions of 15 grams each, subjects will be asked to take 15 g in the morning and 15 g in the night dissolved in 400 ml of water. They will receive a dietary plan with a distribution of 20-30% of protein, 25-30% of lipids, and 40 to 45% of carbohydrates.

Dietary plan with a distribution of 20-30% of protein, 25-30% of lipids, and 40 to 45% of carbohydrates, controlled consumption of alpha-linolenic acid (no more than 6.8 g/day, the amount provided by 30 g of flaxseed).

Changes in 2h-plasma glucose concentration after an oral glucose tolerance test after the intervention (mg/dL)

Changes in insulin resistance after intervention assessed by the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), calculated using insulin and fasting plasma glucose concentrations

Changes in total cholesterol, HDL-C, LDL-C, and triglycerides concentrations after the intervention (mg/dL)

Changes in total physical activity in METs-min/week assessed by the International Physical Activity Questionnaire - Short Form after the intervention

Changes in food intake quality after the intervention assessed by the Mini-Survey to Evaluate Food Intake Quality (Mini-ECCA v.2)

Changes in stool consistency will be assessed with The Bristol Stool Form Scale (BSFS) after the intervention. BSFS classifies stool into one of 7 stool types ranging from type 1 (hard lumps) to type 7 (watery), stool types 1 and 2 will be considered as constipation, stool types 5, 6, and 7 as diarrhea, and Stool types 3 and 4 as normal

Inclusion Criteria: Patients who agree to participate in the study once they have read and signed the informed consent Men and women Fasting glucose levels between 100 and 125 mg/dl Age 30-59 years Stable weight in the last 3 months (no more than 5% weight change) Exclusion Criteria: Fasting glucose <100 and >125 mg/dl Anemia Consumption of drugs that may modify glucose levels Consumption of flaxseed, chia, or omega-3, three months before the study Alternative diets (vegetarian, vegan, ketogenic, etc.) Pregnancy and breastfeeding Allergy or intolerance to flaxseed