Go nuts for nuts!

The UK’s healthy eating model, the Eatwell Guide, encourages us to consume a more plant-based diet - both for our health and the planet. 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. The importance of varying protein intake to include more plant-based sources is also increasingly recognised.

Health authorities, such as USDA and WHO, specifically advocate nuts as part of a healthy diet. Diets low in nuts and seeds (less than 10–19 g/day) were highlighted as one of fifteen dietary risk factors contributing to death and ill health within the Global Burden of Disease study. 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 compared to a control group (who were advised to reduce fat in their diets). Interestingly, eating 30 g of walnuts per day has been found to improve the elasticity of blood vessels, an effect which may be beneficial to heart health.

So, which nutrients can be found in nuts?

Studies looking at nuts and reduced coronary events (e.g. heart attacks) 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 B vitamins, magnesium, phosphorus, copper and manganese (and many types of nuts are also a source of zinc, iron, vitamin E, folate and potassium), as well as containing plant bioactives such as polyphenols and phytosterols and they are also high in fibre. Getting enough fibre reduces our risk of developing heart disease, type 2 diabetes and colon cancer but intakes are well below recommendations in the UK. Nuts can be particularly useful for inclusion in vegetarian and vegan diets as they provide some of the nutrients present in meat and fish (including protein). 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, and those who eat nuts appear to have better quality diets overall, but are we eating a lot of them in the UK? Currently on average we are eating only 6 g of nuts, nut butters and seeds (combined) per day and so subsequently their contribution to our nutrient intake is low (e.g. only around 2% of our fibre and 1% of our protein intakes are derived from nuts, nut butters 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) of plain, unsalted nuts. These do have a high fat (and therefore calorie) content, but the majority of this is ‘good’ (unsaturated) fat and there is some evidence to suggest that the physical structure of nuts (the food matrix) means that our bodies can’t actually extract all of the energy (calories) that's in them when we eat them. 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 are handy for snacking and make a tasty addition to stir fries, curries, stews, pasta dishes, salads, breakfast cereals, porridge and yogurt. 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 and varied plant-based diet may provide benefit. So why not try adding nuts to your diet?