Table 2.
The characteristics of the included studies, summary of dietary interventions, and clinicopathologic features.
| Authors, Year, Country | N, % Women, Age (Mean ± SD), BMI (Mean ± SD), % of Euthyroid Patients, % of Patients Taking LT4 | Duration | Description of the Nutritional Intervention | Results |
|---|---|---|---|---|
| Krysiak et al., 2022, Poland [31] | EG (with non-celiac gluten sensitivity): 31, 100%, 35 ± 7, 22.6 ± 3, 100%, 0% CG (without non-celiac gluten sensitivity): 31, 100%, 36 ± 7, 23.5 ± 3.5, 100%, 0%, 0% |
12 months | EG: Gluten-free diet + vitamin D (100 µg [4000 IU]/day) CG: Gluten diet + vitamin D (100 µg [4000 IU]/day) |
↑ Anti-TPO (p < 0.0017), anti-TG (p < 0.0056) <-> TSH, fT4, fT3, fT3/fT4 ratio |
| Ostrowska et al., 2021, Poland [32] | EG: 45, 100%, 42.74 ± 10.51, 35.63 ± 4.06, nd, 100% CG: 40, 100%, 41.02 ± 11.96, 35.87 ± 5.59, nd, 100% |
6 months | EG (reducing + elimination): Deficit at the level of 1400–1600 kcal + dietary elimination based on the IgG test + 200 mcg of 1-selenomethionine/day and 30 mg of zinc gluconate/day CG (reducing): Deficit at the level of 1400–1600 kcal + 200 mcg of 1-selenomethionine/day and 30 mg of zinc gluconate/day |
↓ Weight (p < 0.001), BMI (p < 0.002), % body fat (p = 0.026), TSH (p < 0.001), anti-TPO (p < 0.001), anti-TG (p < 0.048) ↑ fT3 (p < 0.001) and fT4 (p < 0.001) |
| Pobłocki et al., 2021, Poland [33] | EG: 31, 100%, 36.64 ± nd, 26.27 ± nd, 100%, 100% CG: 31, 100%, 37.07 ± nd, 24.53 ± nd, 100%, 100% |
12 months | EG: Gluten-free diet CG: Gluten diet |
↓ TSH (p = 0.044) <-> fT3, fT4, anti-TPO, anti-TG |
| Farhangi et al., 2020 [34]; Farhangi et al., 2016, Iran [35] |
EG: 20, 85%, 35.70 ± 8.18, 27.10 ± 4.63, nd, 100% CG: 20, 85%, 33.95 ± 8.72, 25.93 ± 4.07, nd, 100% |
8 weeks | EG: Nigella sativa powder 2 g/day (1 g before lunch and 1 g before dinner) CG: Placebo-starch powder 2 g/day (1 g before lunch and 1 g before dinner) |
↓ TSH (p = 0.02), anti-TPO (p = 0.01) ↑ T4 (p = 0.04) <-> weight, BMI, WHR, T3 |
| Krysiak et al., 2018, Poland [36] | EG: 16, 100%, 30 ± 5, 22.9 ± 2.3, 100%, 0% CG: 18, 100%, 31 ± 6, 23.1 ± 2.1, 100%, 0% |
6 months | EG: Gluten-free diet CG: Gluten diet |
↓ Anti-TPO, anti-TG (p < 0.05) <->TSH, fT3, fT4 |
| Esposito et al., 2016, Italy [37] | EG: 108, 50%, nd, nd, nd, nd CG: 72, 44%, nd, nd, nd, nd |
3 weeks | EG: Diet based on the proportions of macronutrients: proteins 50–60%, fats 25–30%, carbohydrates 12–15%. Additional mandatory recommendations: eat vegetables, including large leafy vegetables, and only lean parts of white and red meat. Products such as eggs, dairy products, legumes, fruit, bread, pasta, goitre food, and rice were excluded CG: Low-energy diet with no exclusions as to the type of food consumed, but the patient should follow the recommended diet, according to the assumptions of the National Food and Nutrition Research Institute |
↓ Weight (p < 0.05) and body fat mass (p < 0.05) (in the groups) |
| Asik et al., 2014, Turkey [38] | EG: 38 of LI, 97%, Age: E 45.67 ± 10.28, SCH 35.5 ± 9.87, 79%, 100% BMI: E 27.54 ± 5.77, SCH 30.34 ± 4.59 CG: 12 E without LI, 92%, 47.9 ± 8.73, 29.27 ± 3.67, 100%, 100% |
8 weeks | EG: Lactose-free diet CG: Lactose-free diet |
↓ TSH (p < 0.05) <-> fT4 |
| Yoon et al., 2003, South Korea [39] | EG: 23, 100%, 40.70 ± 10.49, nd, 0%, 0% CG: 22, 86%, 43.50 ± 11.88, nd, 0%, 0% |
3 months | EG: Limiting iodine intake with the diet to 100 mcg per day in a region with excessive iodine intakes CG: No restriction of iodine intake with the diet in a region with excessive iodine intakes |
No investigated correlations between groups |
LI—lactose intolerance, EG—experimental group, CG—control group, BMI—body mass index, E—euthyrosis, SCH—subclinical hypothyroidism, nd—no data, IgG—immunoglobulin G, TSH—thyrotropin, anti-TPO—antibodies against peroxidase, anti-TG—antibodies against thyroglobulin, T3—triiodothyronine, T4—thyroxine, fT3—free triiodothyronine, fT4—free thyroxine, LT4—levothyroxine, WHR—waist-to-hip ratio; ↑ —result higher in the study group than in the control group; ↓—lower result in the study group than in the control group; <-> —the result did not differ between the groups.