Individualized Nutrition Education

Martina Laganà et al. (2025) · Nutrients

This single-blind randomised pilot study with 45 people who have Hashimoto's thyroiditis explored whether a Mediterranean diet or a gluten-free diet changes the body's balance between damaging molecules and antioxidants. Hashimoto's thyroiditis is an autoimmune condition in which the immune system attacks the thyroid gland, and patients tend to show higher oxidative stress, meaning an excess of reactive molecules that injure tissue. The Mediterranean diet is a plant-based pattern built on vegetables, legumes, fruit, nuts, whole grains and olive oil, while the gluten-free diet removes wheat, rye, barley and related grains, and the researchers compared both with simply eating as usual. The study ran at a university hospital in Messina, Italy. Participants were adults aged 18 to 65 with newly diagnosed Hashimoto's, normal thyroid function and no thyroid medication, split evenly into three groups of 15: Mediterranean diet, gluten-free diet or free diet. A dietitian explained each regimen individually, and a three-day food record checked adherence. Blood tests at the start and after 12 weeks measured thyroid hormones, thyroid antibodies and four oxidative-stress markers (AGEs, GPx, TRxR and TEAA). Thyroid hormone and antibody levels did not change significantly in any group, including TPO-Ab and Tg-Ab (the antibodies that mark the immune attack on the thyroid). The Mediterranean diet group, however, showed significantly lower AGEs (advanced glycation end products, damaged proteins linked to oxidative stress) and significantly higher GPx, TRxR and TEAA, which are antioxidant enzymes or overall measures of antioxidant defence (p < 0.001 versus baseline and versus the other two groups). The gluten-free and free-diet groups showed no significant change in these markers (p > 0.05). TPO-Ab fell numerically with the gluten-free diet but not significantly, which the authors read as no relevant effect of gluten restriction on thyroid autoimmunity or function after 12 weeks. In other words, the antioxidant signal appeared only with the Mediterranean pattern. The authors conclude that the Mediterranean diet had a strong antioxidant effect and that a gluten-free diet did not improve redox balance in people with Hashimoto's who do not have coeliac disease. The study has clear limits: only 15 people per group, 12 weeks of follow-up, laboratory markers rather than symptoms or quality of life, and no change in thyroid antibodies, so the findings are preliminary and cannot be generalised to all autoimmune thyroid disorders.

Karolina Osowiecka et al. (2025) · Nutrients

This double-blind randomised study with 64 women who have Hashimoto's thyroiditis explored whether adding a probiotic to nutrition education changes how they feel and function. Hashimoto's thyroiditis is an autoimmune condition in which the immune system attacks the thyroid gland, the gland in the neck that governs metabolism, and it is usually tracked through antibodies called anti-TPO (anti-thyroid peroxidase). Probiotics are live bacteria taken as supplements; the one tested here, Lactiplantibacillus plantarum 299v (Lp299v), is a strain studied for gut symptoms, and the researchers asked whether it adds to the benefits of dietary education. The study took place at a dietetics clinic in Warsaw, Poland. All participants were women aged 18 to 64 with stable thyroid function, most taking levothyroxine. For 12 weeks everyone attended six individual sessions with a dietitian and received a personalised menu. Half also took one Lp299v capsule daily (10 billion bacteria), while half took an identical dummy capsule. Quality of life was scored with the ThyPROpl thyroid questionnaire (0-100, lower is better) and gut symptoms with the GSRS (Gastrointestinal Symptom Rating Scale); blood pressure, body composition, diet quality and anti-TPO were also measured. Both groups reported better quality of life, but the probiotic group improved more. Overall scores dropped by 25.0 points with the probiotic (from 60.94 to 35.94, p = 0.006) versus 14.9 points with placebo (from 54.69 to 39.84, p = 0.043), and the probiotic group improved significantly in 12 of 14 areas while the placebo group improved in 3 of 14. Constipation, abdominal pain and reflux scores favoured the probiotic, and blood pressure, especially systolic, fell more in that group. Anti-TPO antibody levels and body mass index did not change in either group (the immune marker itself did not improve). Diet quality scores rose in both groups, from about 11 to 18.5 points with the probiotic and from about 12 to 19 with placebo, showing that the education alone changed eating habits. The authors conclude that education plus Lp299v improved quality of life and blood pressure without changing the thyroid antibody marker, and suggest that longer and larger trials are needed. The evidence has clear limits: a single clinic, participants recruited through social media, self-reported food diaries, a placebo arm with only about 57% statistical power for overall quality of life, and improvement in both arms, so a placebo or education effect cannot be ruled out. The results apply to euthyroid women with Hashimoto's over 12 weeks and say nothing about long-term outcomes.