This weeks blog focuses on nuts! These little powerhouses of nutrition are fantastically good for us and we should all be eating them more often – read on to find out why!
What are nuts?
Nut is a term used for a group of fruits and seeds that have a hard outer shell and an edible kernel inside. Nuts that are commonly included in the diet include walnuts, pecans, hazelnuts, almonds, brazil, macadamia, peanut, cashew, sweet chestnut, pine nuts, pistachios etc. Note that the coconut is not actually a nut, but a fruit.
Why should we eat nuts?
Nuts are nutritional powerhouses packed with an exceptional variety of beneficial nutrients including protein, fibre, healthy mono-unsaturated fats (as found in olive oil) and essential fatty acids (omega 3 and 6), vitamins (such as vitamin E, B3 and folate), minerals (such as calcium, magnesium, iron and zinc) and trace elements (such as selenium).
Nuts are also a significant source of antioxidant phyto-chemicals (or plant chemicals) and phyto-sterols. Antioxidants are powerful anti-inflammatory substances which inhibit the cell damage that can lead to cancer, heart disease and other chronic health conditions. Phyto-sterols are known to be the single most effective substance for lowering levels of ‘bad’ (or LDL) cholesterol (10), and therefore have an important role to play in reducing the risk of heart disease (20).
How many nuts should we eat, and how often?
Adults should aim to eat 20– 30g of nuts every day (an open handful, or tbsp). Any kind of nuts will do, but raw unsalted nuts are best and variety is preferable in order to obtain the most benefit from the array of different nutrients found in nuts. There is very strong research indicating that people who eat at least 20g of nuts every day have a significantly reduced risk of developing a range of chronic diseases. A large review study carried out by imperial College London (2) found that people who included at least 20g of nuts per day in their diet reduced their risk of;
- cancer by 15%
- heart disease by 30%
- premature death by 22%
- type II diabetes by 40%
This study also found that eating a daily serving of nuts could decrease the risk of developing respiratory infections and other infectious diseases. There are few foods which can make such significant health claims, and based on this evidence there is no doubt that we should certainly all be adding a handful of nuts to our daily diet to protect and promote good health!
Nuts are high in fat, will eating them lead to weight gain?
Whilst nuts are a great source of many nutrients and antioxidants, they are also energy dense due their high fat content. People often assume that nuts should be limited or avoided for this reason because of concerns about their possible contribution to weight gain. However, evidence to date suggests that eating nuts is not associated with weight gain. This is largely because nuts are high in fibre, protein & fat and are therefore very filling; helping to manage hunger levels and prevent over-eating. Moreover studies suggest that the energy (calories) in nuts is not very efficiently absorbed, and so nuts may not contribute as many calories to the diet as we might expect (24).
What is the best way to eat nuts?
Nuts are best eaten raw and un-salted whenever possible, but they can also be eaten roasted or used in cooking. When buying nut butters look for those without added oils, sugar or salt. Store ground nuts in an airtight container in the fridge to prevent their delicate fatty acids from becoming rancid. Nut oils e.g. walnut oil can also be used in moderation, but whole nuts are far much better as they provide more nutrients; oils are not associated with the same benefit as whole nuts.
Pre-soaking nuts in water for a few hours or overnight may improve their digestibility. The idea of pre-soaking nuts is essentially to help break them down so that they are already partially ‘digested’ before they are eaten. This may help the body to absorb the nutrients more efficiently, although there is little research to prove whether or not this is actually so. Therefore it is not essential to pre-soak nuts, but it may perhaps be beneficial for anyone who has a weaker digestive system e.g. the elderly, those with chronic illnesses and anyone with a chronic digestive complaint such as IBS or Crohn’s disease. However there may be health concerns with soaked brazil nuts (34), so it may be wise to eat these nuts as they are.
What is probably more important than pre-soaking for most people is to chew nuts thoroughly before swallowing; this enables all the good nutrients to be released and digested.
Are some nuts better for health than others?
Whilst all nuts are thought to make a positive contribution to health, nuts all have unique nutritional profiles meaning that some may benefit specific areas of health more than others, as follows:
NUTRITION IN A NUTSHELL
- Almonds: (BLOOD VESSELS, BRAIN, BONES) These nuts are very nutrient dense and as such confer many health benefits. Some studies have found eating almonds to be particularly effective at lowering levels of bad cholesterol (8). Almonds are also a very rich source of vitamin E, which has been found to help slow cognitive decline in the elderly (7). They are also a great source of calcium and magnesium, both of which are essential for bone health. Almonds are also a great source of protein required for normal growth and development, as well as the building and repair of muscle tissue.
- Brazil nuts: (THYROID, HEART, BONES, BRAIN/ HEAD) These nuts are an abundant source of the mineral selenium, which is often deficient in the modern diet. Selenium has an important role to play in the immune system (3), in the health of the thyroid gland (4) and plays a role in supporting liver detoxification. NOTE THAT DUE TO THE HIGH SELENIUM CONTENT OF BRAZIL NUTS NO MORE THAN 2 – 3 KERNELS SHOULD BE EATEN PER DAY. Brazil nuts are also high in magnesium which helps to protect heart and bone health and reduce the risk of developing type II diabetes (9). Magnesium has also been found to reduce the frequency and severity of headaches in migraine sufferers (28). Brazil’s also provide a good amount of iron essential for building red blood cells, normal growth and development and the production of some hormones and connective tissue (11). Young children, women of child bearing age and pregnant women are at increased risk of iron deficiency and should take special care to ensure their diet provides plenty of iron rich foods (11).
- Walnuts: (HEART, BRAIN, PROSTATE GLAND) These nuts are rich in omega 3 fatty acids which are known to help protect heart health (5), to be essential for normal brain development in the young, and to help prevent cognitive decline in the elderly (6). Walnuts have also been studied for their ability to both reduce the risk, and improve the prognosis of prostate cancer (25)
- Peanuts: (MUSCLES, HEART) These nuts are officially classed as a legume, and have a very high protein content. As such they are great for supporting healthy growth and development, and for building and repairing muscle tissue. Peanuts are also a good source of fibre, vitamin E, vitamin B3, folate and heart healthy mono-unsaturated fat. Studies suggest that the regular consumption of peanuts can help to reduce heart disease risk by lowering levels of bad cholesterol (18).
- Macadamia: (HEART) This nut has the highest mono-unsaturated fat content of all the nuts and is therefore great for heart health and for lowering bad cholesterol levels.
- Cashew nuts: (SKIN, RED BLOOD CELLS) These nuts are a great source of zinc, which plays important roles in the immune system, bone and skin heath and wound repair (16). Zinc also contributes to the health of the respiratory tract (21). Cashew nuts are also a very good source of iron.
- Pecan: (RESPIRATORY TRACT, GUT, DNA & CELLULAR HEALTH) Like cashew nuts, pecans are a very good source of zinc. In addition to the benefits detailed above, zinc is also recognised for its role in protecting and repairing the health of the gut lining and has been found to be very effective at helping to repair the damage to the gut caused by inflammatory bowel diseases such as Crohn’s (22). Research has also found pecans to have the highest antioxidant capacity of all nuts, meaning that they may help to decrease the risk of chronic diseases such as cancer, heart disease and neurological diseases such as Alzheimer’s (24).
- Hazelnuts: (FETAL DEVELOPMENT) These are a good source of folate; a B vitamin which is vital for preventing neural tube defects in unborn babies, and which may also help reduce the risk of developing some forms of cancer (12). Like many other nuts they are also a good source of heart healthy mono-unsaturated fat, and a reasonable source of iron.
- Pistachios: (MUSCULOSKELETAL MUSCLES & HEART, BLOOD VESSELS) These nuts are rich in potassium, a mineral which is essential for building muscle, for healthy growth and for maintaining the electrical activity of the heart (13). Pistachios also have a high content of phyto-sterols; chemicals which are proven to lower bad cholesterol levels (19).
How can we get more nuts into our diets?
Nuts bring flavour, texture and colour to meals, and different nuts complement different dishes. There are hundreds of creative ways to incorporate nuts into your meals and snacks; try some of the following ideas to get more nuts into your diet!
Add whole or crushed nuts to cereal, muesli or porridge, or try nut butter stirred into porridge, added to a smoothie or spread onto toast.
Add whole nuts such as pine nuts, cashews, almonds or walnuts to salads , or grind and sprinkle them over the top. Cashew nuts can be used in place of cream in soups (just add nuts to the saucepan with the other ingredients, and bled into a creamy soup when done cooking). Use nut butter in place of dairy butter in sandwiches.
Add cashew nuts to curries, stews and stir fries. Walnuts and pine nuts are great with pasta, pistachios fit perfectly with Moroccan and African dishes. Make more nutritious pizza base by swapping some of the flour for ground almonds.
Nuts make a great snack all on their own, or eaten alongside fruit, dried fruit or coconut chips. Alternatively try using nut butter as a dip for crudités or chopped fruit, or spread onto crackers, rice cakes or oatcakes. Cashew nut yoghurt (by ‘Nush’) also makes a healthy snack or dessert.
What about nut allergies?
Nuts can provoke a very severe allergic reaction in a small number of people. If you have a history of nut allergies in the family it is important to be cautious when introducing nuts to new babies in the family. However there is evidence that introducing nuts at a very early age can help to prevent the development of nut allergies in future. Children under five shouldn’t eat whole nuts due to the risk of choking; instead try giving young children nut butters (e.g. spread on toast or bread) and ground nuts mixed into their food.