Nutritional Advice El MondoObjectives:
Polyunsaturated fats (PUFAs) have been shown to reduce type 2 diabetes (T2DM) risk and improve insulin responsiveness in T2DM subjects, but whether the plant sources of omega-3 PUFA (alpha-linolenic acid [ALA]) have an effect on glycemic control requires further investigation. Therefore, this review article (meta-analysis) has been conducted.
Does alpha-linolenic acid dietary intake reduce diabetes risk?
Study design:
This review article included a total of 8 RCTs involving 212 participants with type 2 diabetes.
5 trials (62.5%) were parallel designs and 3 (37.5%) were crossover designs.
Participants were generally middle-aged (median age = 54 years, range = 47-64 years) and overweight or obese (median BMI = 30.7, range = 28.0-33.2).
Overall, participants had controlled diabetes (median HbA1c = 6.8%, median FBG = 7.95 mmol/L) and the majority of studies indicated the use of hypoglycemic drugs or other medications, although all studies excluded the use of insulin therapy.
The dose of ALA ranged from 1.5 to 7.4 g/day with a median assigned dose of 4.4, 5.4 and 5.4 g/day of ALA for trials that reported HbA1c, FBG and FBI, respectively.
The median duration of the treatment was 3 months, ranging from 2 to 12 months.
7 studies (87.5%) were considered high quality (MQS ≥8).
Results and conclusions:
The investigators found compared to a control diet, a median dose of 4.4 g/day of alpha-linolenic acid intake for a median duration of 3 months did not affect HbA1c (%) of patients with type 2 diabetes [MD = -0.01, 95% = -0.32 to 0.31, p = 0.96].
The investigators found compared to a control diet, a median alpha-linolenic acid dose of 5.4 g/day did not lower fasting blood glucose (FBG) of patients with type 2 diabetes [MD = 0 .07, 95% CI = -0.61 to 0.76, p = 0 .84] or fasting blood insulin (FBI) of patients with type 2 diabetes [MD = 7.03, 95% CI = -5.84 to 19.89, p = 0 .28].
The investigators found summary effect estimates were generally compromised by considerable and unexplained heterogeneity [I2 ≥ 75%].
The investigators found in the subgroup analysis of continuous predictors, a reduction in HbA1c (%) and FBG (mmol/L) was significantly associated with an increased intake of ALA.
The investigators found further adjustment for publication bias using Duval and Tweedie's trim-and-fill analysis provided an adjusted, significant MD of 0.25 [95% CI = -0.38 to -0.12, 0.001) for HbA1c (%).
The investigators concluded alpha-linolenic acid-enriched diet with a median alpha-linolenic acid dose of 4.4 g/day during 3 months has no effects on HbA1c, FBG or FBI in patients with type 2 diabetes. The scarce number of existing RCTs and the presence of heterogeneity in the meta-analysis limit the ability to make firm conclusions about alpha-linolenic acid in type 2 diabetes management. The potential for alpha-linolenic acid to have dose-dependent effects warrants further research in this area.
Original title:
The effect of alpha-linolenic acid on glycemic control in individuals with type 2 diabetes: A systematic review and meta-analysis of randomized controlled clinical trials by Jovanovski E1, Li D, […], Vuksan V.
Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5457843/
Additional information of El Mondo:
Find more information/studies on PUFA and diabetes right here.
4.4 g/day alpha-linolenic acid can be achieved by taking 1 to 2 tablespoons of flax or salba-chia seeds or about 12 whole walnuts per day.