8 May 2017
Dr Stacey Lockyer
The UK’s healthy eating model, the Eatwell Guide, encourages us to consume a more plant-based diet - both for our health and the environment. This is not to say that animal foods need to be excluded completely - meat is an important source of iron and zinc, dairy is important for calcium and iodine and oily fish for long chain omega 3 fats and vitamin D; but plant foods, particularly fruit, vegetables and wholegrain or higher fibre starchy foods should be making up most of our diet.
Health authorities, such as USDA and WHO, specifically advocate nuts as part of a healthy diet. A number of observational studies report that people who eat more nuts tend to have a lower risk of heart disease, cancer and death from all causes, and evidence from controlled trials further suggests that eating nuts can help to reduce blood cholesterol. PREDIMED, a study in which one arm of subjects followed a Mediterranean diet and ate 30 g of mixed nuts per day, found a significantly lower rate of heart attack, stroke and death from heart disease and interestingly, eating 30 g of walnuts per day has been found to improve the elasticity of blood vessels which may reduce heart disease risk.
So what nutrients can be found in nuts?
Studies looking at nuts and reduced coronary events often mention that the unsaturated fats in nuts may play a key role in the beneficial outcomes reported. However, nuts are also a source of micronutrients such as magnesium, potassium, iron, zinc, selenium, vitamin E and B vitamins and they are also high in fibre. Getting enough fibre reduces our risk of developing heart disease, type 2 diabetes and colon cancer. Nuts are also a plant based protein source, and can be particularly useful for vegetarians and vegans as they provide some of the nutrients present in meat and fish. There is also some evidence that foods rich in protein and fibre can help us feel fuller – an important aspect in weight management.
It would seem then that nuts are nutritious, but are we eating a lot of them in the UK? Currently on average we are eating only 2 g nuts and seeds per day and so subsequently their contribution to our nutrient intake is low (e.g. only around 1% of both our fibre and protein intakes are derived from nuts and seeds). Perhaps this is because the traditional bag of roasted, salted nuts is considered to be ‘fattening’. Flavoured and coated nuts do contain added oil, salt and/or free sugars and so the better option is to go for small amounts (such as a handful, around 30 g) of plain, unsalted nuts. These do have a high fat content, but the majority of this is ‘good’ fat (unsaturated). Overall, plain nuts offer more essential nutrients than foods such biscuits, cakes and crisps, and so are a better choice of snack.
Including nuts in your diet
Nuts can be handy for snacking and make a tasty addition to stir fries, curries, salads, breakfast cereals and homemade cereal bars. Nut butters have increased in popularity, with new varieties such as cashew and almond butters offering us more choice. These can be great on wholegrain toast or in sandwiches, and as a dip for fruit or rye crispbread but do opt for those without added sugars or salt and again, watch your portion sizes. If you like nut butters in smoothies, just add a tablespoon and remember that smoothies should be limited to 150 ml per day.
Just adding a handful of nuts to a poor dietary pattern is unlikely to lead to significant improvement in health outcomes, but including nuts as part of a healthy, balanced diet may provide benefit. So why not try adding nuts to your diet?!