Peanuts are a good food. Plenty of protein (over 20%), dietary fiber (8%), the B vitamins, and minerals such as iron, magnesium, zinc and phosphorus. While fat levels are very high (up to 50%), they are mainly the healthier monounsaturated fats with much smaller amounts of saturated fats (1). Peanut butter, is essentially a paste made from roasted peanuts and a tasty spread very popular with children. On a recent visit to the supermarket I was pleased to find peanut butter in a glass, rather than a plastic container so I bought a jar. I have discussed my concerns about using plastic container for oil rich foods like peanut butter in earlier blogs and in some detail in the Promoting Good Health book “The Silent Threat” which is available through our website. My concern is the possible migration of oil soluble plastic components from the container into the food.
Shortly after I bought the peanut butter, I had a visit from my grandchildren both of whom love peanut butter. Imagine my surprise then when they would not eat the peanut butter in the glass jar I had bought. They both said it had no taste! This got me thinking. Scientists are like that. What was different about the peanut butter in the glass jar? Fortunately I had another jar of peanut butter in the cupboard, in a plastic container. When I gave this peanut butter to my grandchildren they took to it with some relish. So what was different between the two different peanut butters?
I suspected there was something in one of the peanut butters not in the other. An examination of the two labels soon confirmed this. The peanut butter in the glass jar, was labeled as “naturally chemical and preservative free”. It contained 100% roasted peanuts and apparently, nothing else. On the other hand, the peanut butter in the plastic container, also labeled as “no artificial colors, flavors, or preservatives” contained not just freshly roasted peanuts (90%) but vegetable oil, sugar, and salt. So the peanut paste in the glass jar was just peanuts, while the peanut paste in the plastic container was a mixture of peanuts, an unidentified oil, sugar and salt. Further enquiry revealed the unidentified oil was canola oil, a variety of rapeseed and 3 grams of sugar and nearly 600 milligrams of salt had been added for every 100 grams. It is unlikely the difference in flavor detected by my grandchildren was the canola oil, which has a fairly bland taste, so it was most likely the added sugar and salt.
So what if there is added salt and sugar in peanut butter? After all, the average amount of peanut butter put onto a slice of bread is not very great and the sugar and salt content is a lot less than, for example, the sugar we add to our tea or coffee, or the salt we add to a plate of food we have prepared in our own kitchen. The real issue is one of control. When we prepare food, we are in control of what we add to it. However if it has been added to the food before we get to it, there is nothing we can do. Someone else is in control. Why do food manufacturers and retailers believe a natural and healthy food like peanut butter has to be tampered with to create something more satisfying for consumers? And it is not just peanut butter but most processed food, whether it is breakfast cereal, baked beans, hot dogs, or cold meats have salt and sugar added to it. Of course, if children start eating processed food containing extra salt and sugar from an early age, they get used to the taste and it becomes the norm for them – perhaps for the rest of their life! For many, once hooked on lots of salt and sugar in their food, and particularly from an early age, it becomes very difficult to reduce their intake because food seems to lack taste or they need the sugar rush.
For now we’ll just concentrate on salt – we will discuss added sugar some other time. You can get an idea of how much salt is present in a food by looking at the sodium content shown on the food labels. While the sodium content of fresh food, such as beef, fish, vegetables, fruit or milk, is rarely greater than about 90 milligrams per 100 grams, the corresponding values for processed foods can be as high as 1,400 milligrams per 100 grams. The highest sodium content I came across was in one brand of prosciutto, a type of bacon, with a value of 2,240 mg per 100 grams (most bacon is over 1,000 mg). This is a truly amazing amount and more than 30 times greater than the 50-80 milligrams of sodium present in the fresh pork from whence it came. And let us not forget:
Soy sauce, with a sodium content of more than 6,000 milligrams per 100 grams.
British marmite, a yeast extract spread popular with children, with a sodium content of more than 3,000 milligrams per 100 grams.
It is easy to see how, in the diet is rich in processed food, the intake of salt can reach levels many times the Reference Nutrient Intake (RNI) for sodium of around 1,600 milligrams per day, the amount considered sufficient to sustain normal health and wellbeing (2).
So, why is the extra salt in processed food a problem? Well, there is considerable evidence that high salt intake is a factor in the development of hypertension (high blood pressure) and this in turn can increase the risk of heart and kidney diseases, stroke, and perhaps gastric cancer (3, 4). There are also some indications salt can contribute to some of symptoms of Meniere’s disease, a disorder of the inner ear, which can give rise to deafness, tinnitus and severe vertigo (5). The problem of excessive salt intake worldwide has been recognized by various world and national government agencies, such as the World Health Organization, the UK Food Standards Agency, and the US Federal Drug Administration Agency (FDA) (6, 7). Given the convincing evidence for the potentially harmful long term effects of high salt consumption, it makes sense to reduce your intake of processed foods and, where possible, eat fresh food instead. However, if you do buy processed food, you would be wise to look closely at the sodium content and other the other information provided on food labels. In doing so, you and not the retailer or manufacturer, decides what is best for you.
Meanwhile, stay happy and healthy!
(1) USDA / ARS Nutrient Data Laboratory: USDA National Nutrient Database for Standard Reference. The USDA National Nutrient Database is available online at: http://www.nal.usda.gov/fnic/foodcomp/search/
(2) Garrow, J. S.; James, W. P. T. and Ralph, A.; Human Nutrition and Dietetics. 10th edition. Churchill Livingstone. 2000.
(3) He, F. J. and MacGregor, G. A.; J. Hum. Hypertens., 23, 363-384, 2009.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/19110538
(4) Wang, X. Q.; et al World J. Gastroenterol., 15, 2204-2213, 2009.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/19437559
Full article available online at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2682234/pdf/WJG-15-2204.pdf