The festive season always makes me think of nuts – the ballet The Nutcracker, the bowl of mixed unshelled nuts, the smell of roasting chestnuts…
As nutrition scientists, we also know that nuts are a nutrient dense food. They provide a source of protein, minerals such as magnesium, iron and zinc, vitamins like vitamin E and some of the B vitamins, fibre, and essential fatty acids.
New review suggests handful of nuts may be beneficial to health
I was reminded of nuts again in this festive season with a new review that concluded that eating a serving of nuts daily (28 grams, the equivalent of a handful a day) was associated with a reduced risk of heart disease, cancer and death from any cause.
Previous studies have also suggested an intake of nuts is beneficial to health. Some have found it could be linked with reduced risk of cardiovascular disease and cancer. Other studies, though, have found no link.
Now a research team from Imperial College, whose findings appear in the journal BMC Medicine, have analysed published data on more than 800,000 participants from around the world. Their study covered all kinds of tree nuts, such as hazelnuts and walnuts, as well as peanuts, which are technically legumes.
By performing a systematic review the authors pooled together the results of many nutrition studies, looking at nut intake and health. But systematic reviews are only as good as the studies included. Studies looking at dietary factors are often observational and it is difficult to rule out the possibility of confounding variables from other health and lifestyle factors. People with a high intake of nuts, for example, tend to be less likely to smoke, to be slimmer and more physically active, and to have a lower intake of red and processed meat and a higher intake of fruits and vegetables than persons with a low nut intake. Although researchers try to account for all of these variables, it is unlikely that they can.
Is it the nuts or is it a healthier lifestyle?
So it’s hard to discount the possibility that nuts could be just one component of a healthier diet and lifestyle pattern. It could be this overall picture that is reducing risk, not just nuts.
Results from observational studies alone then cannot be used to draw conclusions with regards to whether the associations between nut consumption and health are causal. A randomised trial (the PREDIMED study) also found a reduced risk of cardiovascular disease, as well as a cognitive decline in subjects, randomised to a Mediterranean diet with nuts compared to subjects randomized to a control diet. However, it is not clear if this association is due to the Mediterranean diet component, nuts, or a combination of the two.
Care must be taken for people with nut allergy or at risk of choking
So research suggests a benefit to including nuts in the diet. Nevertheless, some people are allergic to nuts and peanuts, and whole nuts may not be suitable for some residents who have difficulty swallowing or are at risk of choking.
Nuts can be used in a ground, creamed or pasted form (like smooth nut butters) to make their consumption easier, and are a good source of protein and energy for service users at risk of malnutrition, as well as providing many essential nutrients that may be inadequate in the diet of those with generally low food intake. Nut butters can be used as a snack on bread and in sweet or savoury recipes – even in a high energy milkshake!
And of course, the nut roast is the traditional alternative to the turkey! Merry Christmas 2017 readers.
