Eating sustainably…
are any nutritional considerations needed?
What is a sustainable diet?
The terms sustainable diet and plant-based diet are still misunderstood by many of the population, with many thinking they mean a vegan diet. However, both terms can include some meat, fish, eggs and dairy.
A sustainable or plant-based diet means a move to a dietary pattern that has a greater emphasis on foods derived from plants. This means foods such as fruits and vegetables, whole grains, pulses, nuts, seeds, and oils, but can include smaller amounts of meat, poultry, fish, eggs and dairy products.
When considering the nutritional implications of a sustainable/plant-based eating pattern, it is important to grasp what this looks like. And then to understand what, if any, are the relevant nutritional considerations.
What our current diet looks like
In the most general terms, as a population our current diet is not sustainable or healthy. The most recent UK National Diet and Nutrition Survey (NDNS) data shows that our population’s intakes of saturated fat, sugar and salt are above the Government recommended levels, whereas intakes of fibre, fruit, vegetables, and oily fish are below Government recommendations. Our current dietary habits are fuelling obesity, type 2 diabetes, heart disease and some cancers.
What does a sustainable diet look like?
In the UK, the Eatwell Guide provides a model for a healthy, varied diet. It is estimated that if everyone in the UK adopted this diet, it would lead to reductions in associated GHGE (45% lower) and land use (49% lower). Following the Eatwell Guide means eating at least 5 portions of fruit and vegetables a day, wholegrain and higher-fibre starchy foods, and diversifying protein intake more towards plant sources. This includes beans and other pulses, as well as plant-based meat alternatives. It also includes nuts if safe to do so, alongside eggs, some dairy foods or alternatives, and sustainably sourced fish. This should be done whilst also limiting consumption of foods high in fat, salt, and sugar.
A recent study found increased adherence to the recommendation on reducing red and processed meat consumption was associated with the largest decrease in environmental impacts and carbon footprints.
This same study found that if everyone in the UK consumed a diet in line with these recommendations, it would lead to significantly less type 2 diabetes, coronary heart disease, stroke and cancer.
What are the specific nutritional considerations of a sustainable diet?
Here we set out some of the specific nutritional considerations of moving towards a more environmentally sustainable diet.
Protein:
Protein is often the nutrient of concern when switching to a more sustainable diet. A summary of evidence from the BDA’s The One Blue Dot has shown that neither protein quality nor quantity is compromised when switching to more plant-rich diets. This is true whether meat and dairy are included at reduced quantities or if they are totally excluded. Plants contain all essential amino acids and vegan diets can meet all essential amino acid requirements.
Current UK protein intakes exceed the recommended daily intake, including those following a vegan diet (The One Blue Dot).
Protein tip: Protein intakes are already in excess of nutritional requirements. Reducing meat will not negatively impact protein intake if replaced with a variety of different plant-rich proteins. Beans and lentils are particularly nutritious, often described as power houses for nutrition as they are high in protein, fibre and micronutrients as well as having the bonus of being cheap.
Fibre:
Our current diets are particularly poor when it comes to meeting our fibre requirements. In the UK, the average fibre intake for adults is only 18g a day. The recommendations for fibre intake are; 30g per day for adults, 20g for 5-11 year olds and 25g for 11-16 year olds.
There is strong evidence that diets rich in fibre, particularly cereal fibre and wholegrains, are associated with a lower risk of many health conditions, including cardiovascular disease, coronary events, stroke, type 2 diabetes and colorectal cancer.
Fibre tip: A sustainable diet will increase your fibre. Beans, lentils, fruit and vegetables are all high fibre sources and eating more of these is likely to have positive health benefits.
Iron:
Red meat is a key source of iron. Low iron stores remain an issue for young women in westernised societies, however the prevalence of iron deficiency anaemia (low haemoglobin levels) remain relatively low. SACN indicates that reducing red meat in high consumers (90g+ /day) will not compromise iron intakes.
However, in more vulnerable groups – such as toddlers, girls and women of childbearing age – low iron intake is a concern. Low iron stores remain a health issue (even with current high intakes of red meat). However interestingly there has actually found to be no difference in the prevalence of anaemia between vegans, vegetarian, and omnivores.
Evidence of an increase in iron deficiency anaemia amongst those consuming diets mostly based on plant foods, such as vegetarian diets, is lacking.
Iron tip: Iron requirements can be achieved by ensuring plenty of plant-rich iron sources such as fortified breakfast cereals (preferably not ultra-processed or high sugar options), as well as nuts, seeds and vegetables, are eaten, and by including red meat in small amounts. This is particularly relevant if there is concern around iron intake for more vulnerable groups, such as young girls or older adults with low intakes.
Zinc:
Red meat is also a key source of zinc. Teenage boys and girls have significantly low intakes. Plant sources, with the exception of mycoprotein, are lower in zinc. SACN modelling estimates that red and processed meat contributes 32% of men’s total zinc intake and 27% of women’s.
Zinc tips: Consuming a small amount of meat will likely achieve zinc requirements. Including more seeds and choosing wholemeal/wheatgerm breads will also contribute to zinc intake as well as including Quorn as a meat alternative, which has a similar content to beef. Vulnerable groups not consuming any red meat may benefit from taking a nutritional supplement.
Calcium:
Most non-organic plant-based drinks are calcium-fortified with a similar content and bioavailability to dairy milk. Therefore switching some or all dairy milk consumption to plant-based milks or yoghurts will have no significant detrimental effect on calcium intake.
Calcium tip: Switching some or all of milk consumption to plant-based drinks will have little or no impact on calcium intake due to fortification of these products, however be careful with organic products as these may not be fortified.
Iodine:
The majority of plant-rich drinks are not fortified with iodine. However, although dairy does contribute to iodine intake, if some dairy is still being consumed along with small amounts of other animal foods such as fish, seafood, yogurt and eggs, it is likely that adequate iodine intake would be achieved. Some vulnerable groups on a vegan diet may need to consider the use of an iodine-containing supplement.
Iodine tip: If still consuming small amounts of meat, fish and dairy, a deficiency of iodine is unlikely to be an issue. Plant-based sources include wholemeal bread, lentils, seeds, beans and tofu. Some people on a fully vegan diet, however, may need to consider a supplement.
Vitamin B12:
Vitamin B12 is only available from animal sources and a few fortified plant foods. For most adults still consuming reduced amounts of meat, dairy, and eggs, achieving recommended amount should not be a challenge.
Vitamin B12 top tips: A reduced amount of meat, fish and diary is unlikely to impact on B12 status, as only a small amount of these foods is needed to meet requirements. Plant-rich sources include fortified breakfast cereals and plant based milk, and Marmite. A vegan diet would need a supplement.
Omega 3:
A sustainable diet includes 2 portions of fish a week, one of which should be oily to ensure sufficient omega 3 fatty acids EPA and DHA.
Omega 3 tips: Aim to follow the Government recommendation for 2 portions fish per week, one being oily, to meet Omega 3 recommendations. Those not eating fish will need to include nuts and seeds such as walnuts and pumpkin seeds, or consider a supplement to meet Omega 3 requirements.
Key take home messages on eating sustainably
All the evidence shows moving to a more plant-rich diet will have a positive impact to our health and will meet our nutritional requirements.
A sustainable/plant-based way of eating doesn’t need to be vegan or vegetarian, and can include small amounts of meat, fish, and dairy.
For this reason, for the majority of us, there is no negative impact, but only positive health – and also sustainable – benefits.
So, what’s stopping you? Open that tin of beans or lentils and add some to your dish today!