In general, the salt in our diet is made from the pairing of sodium and chlorine ions. These ions naturally combine and are abundant in seawater, in the earth’s crust and in our bodies. Sodium chloride has been extensively used throughout the ages as a food preservative for meats and butter, as a flavouring agent for bread and breakfast cereals, as a texture enhancer for cheese and as a raising agent in baked goods. It has been a prized commodity with the Romans being paid in salt, and so you were deemed to be ‘worth your salt’ if you got paid.
Nowadays, Westernised societies have an aging population, who are living longer with chronic conditions such as hypertension (high blood pressure) and coronary heart disease. It has been shown that the increased prevalence of these conditions is due to environmental factors such as diet and exercise rather than from genetics. A key contributor to high blood pressure and consequently heart disease is the amount of sodium (from salt) in the diet. The results from the landmark Dietary Approach to Stop Hypertension trial confirmed this (Sacks et al., 2001).
Sodium is crucial in the body as it has electrochemical properties. It is required to maintain the balance of body fluids in their compartments, including blood volume. It is also essential in the function of nerve impulses and muscle contractions. Without it, the body just would not function.RELATED: RECOMMENDED PLANS FOR YOU
We are able to maintain a relatively constant range of sodium in the blood by way of the kidneys. If too much sodium has been consumed, the kidneys excrete more sodium out in your urine. However, there is a limit to how much sodium the body can cope with. It has been extensively shown in trials that high intakes of sodium in salt, cause it to be retained in the body and so puts the kidney under strain. This in turn leads to higher blood pressure, also known as hypertension. This condition increases the incidence of stroke, coronary heart disease, heart attacks and renal failure.
The kidneys can also conserve sodium and limit the amount excreted during times of depletion. Body levels of sodium can be depleted during activity that leads to heavy sweating, or during times of vomiting and diarrhoea. This is when higher intakes of sodium are required to replace losses and maintain normal body levels.
The current United Kingdom (UK) guidelines by the Scientific Advisory Committee on Nutrition (SACN, 2003) states the daily recommended nutrient intake (RNI) for sodium is 2.4g/100mmol. This is equivalent to 6g salt per day. The National Diet and Nutrition Survey (Hoare et al., 2004) highlighted that 85% of men and 69% of women in the UK, were consuming more sodium than the RNI. The risk of developing hypertension increases with age. The prevalence of high blood pressure if you are over 75 years old is around 70%, whereas it is only 3% for 25-34 year olds. It is a global public health issue to reduce the amount of sodium in the diet of adults. If the number of people with hypertension decreases, there will be more people with healthy hearts and bodies.
So, you may now be wondering how you avoid sodium in your diet. The short answer is you cannot. The body needs some sodium to maintain the body levels and replace daily losses from normal bodily functions. However, we know the majority of people are eating too much. Some people use salt in cooking and add it to food at the table. However, around 75% of the salt we eat is from ‘hidden’ sources in processed foods. This is why it is so hard to know just how much sodium you are eating.
Tips for lowering your sodium intake for a healthy heart
– A diet rich in fruit, vegetables and low fat dairy products will generally be lower in salt (DASH trial). By eating five portions of fruit and vegetables and eating as close to a foods natural state will keep your diet low in sodium as well as being good for weight loss.
– Processed foods contain the hidden sources of sodium. Therefore, pay attention to food labelling. The traffic light system will give you an indication of the sodium or salt content. If it’s indicated as green, it’s a go (0.3g salt, or 0.1g sodium per 100g).
– Good news! As your taste buds have become accustomed to a certain level of flavour from sodium, you can wean yourself off the taste. There are some low salt alternatives to table salt, or try using herbs, spices and citrus juices instead for flavour. Decreasing your intake on a weekly basis will help to allow your taste buds to become accustomed to it.
– Foods that taste salty, contain too much sodium. These include foods such as gravies, sauces, pickles, bacon, baked beans, biscuits and crisps. So, look for lower salt varieties on the supermarket shelf.
5 heart healthy low sodium snacks
- Change your sausages, ham and bacon for chicken, turkey, fish or beef meats.
- Swap yeast extract or peanut butter for unsalted butter and mashed banana, or honey on top of your bread.
- Change hard cheeses, such as cheddar for soft spreadable cheese or eggs
- Swap crunchy crisps and biscuits, for crunchy cucumber, celery and carrots
- Change your cereal for reduced salt alternatives or a cereal bar, yoghurt and fresh fruit.
Also check out these 10 Low Calorie Snacks
1. Hoare, J. and Henderson, L. (2004) The National Diet and Nutrition Survey. The Stationary Office: London. Accessed at http://multimedia.food.gov.uk/multimedia/pdfs/ndnsv3.pdf
2. Scientific Advisory Committee on Nutrition (2003) Salt and Health. The Stationary Office: London. Accessed at http://www.sacn.gov.uk/pdfs/sacn_salt_final.pdf
3. Sacks, F.M., Svetkey, L.P., Vollmer, W.M., Appel, L.J., Bray, G.A., Harsha, D., Obarzanek, E., Conlin, P.R., Miller, E.R. 3rd, Simons-Morton, D.G., Karanja, N. and Lin, P.H. DASH-Sodium Collaborative Research Group (2001) ‘Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet.’ New England Journal of Medicine. 344(1), pp. 3-10.
British Heart Foundation http://www.bhf.org.uk/
Change for Life http://www.nhs.uk/change4life
Food Standards Agency http://www.food.gov.uk/scotland/scotnut/salt/