Risk-benefit analysis of Scottish seaweeds as a sustainable food source

Challenges

Greenhouse gas (GHG) emissions are inherent in food production but GHG mitigation strategies within agriculture may conflict with the need to provide healthy, nutritious food and diets. Shifting food production away from meat and meat products towards more plant-based diets may lower dietary micronutrient levels (e.g., vitamin B₁₂, iron), potentially affecting health. Indeed, dietary change among UK consumers is already underway with those reported to be following a meat-free diet, (around 2% in 2012), increasing to 10% currently and predicted to double by 2025. Therefore, there is a need to provide alternative, sustainable sources of important dietary micronutrients that are predicted to decrease as agricultural and consumer practices transform to address the climate emergency and the need to achieve Net Zero.

Scottish seaweed as a sustainable food source

Seaweeds (macroalgae) could provide one alternative dietary source of many of the micronutrients traditionally obtained from animal products. Studies on some seaweed species have shown that marine algae can be rich sources of micronutrients. In addition, algae can provide a valuable alternative source of other macronutrients including protein and fibre, as well as containing useful amounts of essential omega-3 fatty acids. 

Seaweeds can also act as a natural low-salt replacement in foods, where the salty flavour is made up mainly of minerals including potassium and magnesium in addition to sodium. Moreover, as seaweeds and microalgae are responsible for producing most of the oxygen in the atmosphere and fixing most of the carbon dioxide, cultivation may contribute significantly to attaining targets for national GHG emissions. Seaweeds also grow in seawater and therefore do not compete for arable land or freshwater with other land-based crops and foods. 

The global demand for macroalgal (and microalgal) food is expanding and displaying enormous potential for applications within the feed and food industries. Currently, seaweed production is dominated by wild harvesting, but seaweed farming and aquaculture are emerging industries and will greatly increase production levels. The nutritional content and healthiness of native Scottish seaweeds are, however, less well established. Moreover, an assessment of any nutritional benefits of seaweeds to the consumer needs to be balanced by any potential risks of consumption, as certain seaweed species can contain heavy metals and as well as potentially unhealthy high levels of iodine. 

Questions

Solutions

This project aims to test the evidence that Scottish seaweeds can provide rich, sustainable, plant-based sources of essential dietary micronutrients with an eventual goal to include these as dietary ingredients within food products.

Establishing sustainable sources of essential micronutrients within Scottish seaweeds 

Dietary intakes of certain important dietary micronutrients are envisaged to decline as consumers shift from animal protein-based to plant-based diets. Seaweeds could provide one sustainable source of many of these micronutrients. We have previously determined levels of heavy metals and iodine within a range of Scottish food products, which included a limited range of seaweed species. This preliminary research indicated that the health risks from heavy metals and iodine from consuming seaweeds are species-dependant, and that consumption of many seaweed species would present a low health risk. We have continued and expanded this work to define which species can provide safe sources of nutritionally relevant levels of micronutrients for human consumption. 

This project will source and prepare a range of commercially relevant Scottish seaweeds (brown, red and green microalgae) to: 

• Determine the levels of micronutrients including vitamin B₁₂, within these seaweeds
• Quantify the levels of heavy metals and iodine within these same seaweeds
• Evaluate and report on the different seaweed species, both for their potential to provide nutritionally relevant levels of micronutrients and their potential risk to consumer health due to their heavy metal/iodine content. 

Data analysis, micronutrient levels and risk assessment of heavy metals

We address a knowledge gap regarding levels of dietary-relevant micronutrients as well as heavy metal content within Scottish seaweeds that will assist the sector to prioritise and target those Scottish seaweed species that can be utilised in high value food products. Additionally, this data will help identify those seaweed species that may pose a risk to health and help to manage these components within the food supply chain. 

We are developing an openly available dataset of levels of both micronutrients and heavy metals for each seaweed species including data on location and collection method where relevant. 

Overall, this project will help to establish commercially relevant Scottish seaweeds with beneficial levels of important plant-based micronutrients to provide the industry with key product data and added value and ultimately provide consumers with an alternative, sustainable source of these nutrients.

Project Partners

Progress