The valorisation of bioactive compounds from seaweeds is of interest due to their abundance and diverse range of bioactive compounds, which are crucial for the development of novel nutraceutical products. Recently, a unique composition of seaweed extracts, consisting of a blend of brown seaweeds Ascophyllum nodosum and Fucus vesiculosus), has emerged as a potential therapeutic solution for immunological and metabolic abnormalities. This thesis sought to investigate the clinical efficacy and safety of these extracts and to determine the optimal dosage for the management of metabolic syndrome components and inflammation. This thesis is divided over five chapters; in Chapter 1, I presented a general introduction to seaweeds, in particular brown seaweeds and their main metabolites, as they are known to contain more bioactive components compared to red and green seaweeds. In Chapter 2, I presented the first comprehensive review of two extensively studied brown seaweed extracts, Ascophyllum nodosum and Fucus vesiculosus, with respect to their efficacy in managing and preventing metabolic syndrome and its associated comorbidities. The findings shed light on the promising potential of these extracts in managing metabolic syndrome and its related disorders. To address the heterogeneity observed in previous study results, I conducted dietary intervention studies to determine the potential benefits of these extracts in the context of metabolic health among a non-habitual seaweed consuming UK population. In Chapter 3, I presented the results of a preliminary pilot study aimed at evaluating the impact of seaweed extracts on fasting blood glucose, insulin, insulin resistance (HOMA-IR), blood lipids, gastrointestinal symptoms, and to assess product tolerability in terms of side effects in overweight and obese adults. The results showed a trend towards a reduction in plasma glucose and low-density lipoprotein cholesterol and an increase in high-density lipoprotein cholesterol after two-weeks of treatment with 700 mg of seaweed extracts. In addition, the study showed that the administration of these extracts to 12 overweight and obese adults was well tolerated, with no reported side effects or adverse impacts on gastrointestinal function. In Chapter 4, I conducted the first dose response study to date investigating the effects of seaweed extracts on metabolic syndrome components, inflammatory markers and gastrointestinal health. The results demonstrated with the efficacy of 500 and 700 mg of seaweed extracts in reducing systolic blood pressure, non-HDL-C, glycated haemoglobin and levels of the pro-inflammatory cytokines IL-2, IL-4, IL-10, TNF-α, and increasing IFN-γ within a relatively short period of 4 weeks, with no associated adverse effects. Overall, this thesis provides valuable insights into the potential of brown seaweed extracts, specifically A. nodosum and F. vesiculosus. The findings highlight that treatment with 500 and 700 mg of seaweed extracts was effective in managing metabolic syndrome components and reducing inflammation. These beneficial effects were achieved without any adverse effects on gastrointestinal function, even within a relatively short period of time and importantly, paves the way for further studies on this topic.
- brown seaweeds
- metabolic syndrome
- Ascophyllum nodosum
- Fucus vesiculosus
Exploring the therapeutic potential of brown seaweed extracts (Ascophyllum nodosum and Fucus vesiculosus) in the management of metabolic disorders, inflammation, and gastrointestinal health
Keleszade, E. (Author). 11 Jun 2024
Student thesis: Doctoral Thesis