RESUMO
BACKGROUND: Lymphoedema is a chronic and progressive disease characterised by excessive accumulation of lymph in the interstitial compartment, leading to tissue swelling and fibroadipose deposition. Lymphangiogenesis is partly regulated by ketone body oxidation, and a ketogenic diet (KD) has shown therapeutic efficacy in a preclinical mouse tail lymphoedema model. Therefore, we aimed to investigate the potential therapeutic effect of a KD in patients with secondary lymphoedema. METHODS: Nine patients with unilateral stage 2 lymphoedema secondary to lymphadenectomy were included in this quasi-experimental exploratory study consisting of a short run-in phase to gradually induce ketosis, followed by a classic KD (CKD) and modified Atkins diet (MAD) phase during which patients consumed a CKD and MAD, respectively. Lymphatic function and oedema volume, the primary outcomes, were assessed at baseline and at the end of both the CKD and MAD phase. Secondary outcomes included health-related and lymphedema-specific quality of life (QoL). RESULTS: Seven out of nine patients completed the study protocol. Lymphatic function was improved upon consumption of both a CKD (dermal backflow score [mean ± SD]: 7.29 ± 2.98 vs. 10.86 ± 2.19 at baseline; p = 0.03) and MAD (6.71 ± 2.06; p = 0.02), whereas oedema volume did not decrease during the course of the study (excess limb volume [mean ± SD]: 20.13 ± 10.25% at end of CKD and 24.07 ± 17.77% at end of MAD vs. 20.79 ± 12.96% at baseline; p > 0.99 and p > 0.30, respectively). No changes were observed in health-related, nor lymphoedema-specific QoL at the end of CKD and MAD. CONCLUSIONS: The consumption of a KD improved lymphatic function and was associated with a clinically meaningful reduction in oedema volume in some patients (3/7 at end of CKD, 2/7 at end of MAD) with unilateral stage 2 secondary lymphoedema. These results highlight the potential of a KD to improve lymphatic function in patients with lymphoedema. However, further studies are required to substantiate our findings.