Salt and Black People of African Descent

Introduction

Salt has many detrimental effects on health and is considered one of the most important risk factors for high blood pressure, the consequence of which is increasing the risk of heart attacks, strokes and heart failure.

Many people from ethnic minorities living in the UK, including black people of African descent (accounting for around 2% of the total population in the UK (1)) are particularly sensitive to the effects of too much salt and are therefore at higher risk of associated health conditions such as stroke and renal failure.

The effect of salt

There is evidence to show that black people of African descent living in the UK are three to four times more likely to have high blood pressure compared to white populations in the UK.(2-4) They have also been shown to have double the stroke mortality compared to the UK general population (5) as well as an increased risk of end stage renal failure (5) both of which can be caused by high blood pressure.

A number of studies(7-9) including the Dietary Approaches to Stop Hypertension (DASH) study, have shown that reducing salt intake can lower blood pressure to a greater extent in the black population compared with the white population. Another study (10) demonstrated that a modest reduction in salt intake (from around 10g to 5g of salt per day) in black patients with high blood pressure resulted in both a fall in blood pressure (the major risk factor for cardiovascular disease) and urinary protein excretion (the major risk factor for renal disease and an independent risk factor for cardiovascular mortality). The fall in BP with salt reduction is equivalent to that seen with single drug treatment. It has been predicted that reducing salt intake from the current levels to 6g a day in black people of African descent could reduce their risk of a stroke by 45% and heart disease by 35%.(11)

 BP Blood pressure, UPE Urinary Protein, UNaE Urinary Na

Figure 1 – the effect of modest salt reduction on on BP and urine protein excretion  in  black hypertensives. (10)

Current salt intake

Almost everyone in the UK (and the rest of the Western world) eats too much salt. The daily recommended amount in the UK is no more than 6 grams a day; the current average salt intake is 8.1g salt a day although many people are eating more than this. People with or considered at risk of high blood pressure should take extra care to ensure that they keep their salt intake below the recommended maximum of 6g.

The majority of salt consumed by people of black African descent is from salt added in cooking and/or at the table. This is in contrast to the rest of the UK population (and indeed the Western world) where 75% of salt intake comes from processed foods. A health survey in England12 found that 83% of black men and 85% of black women added salt in cooking. Over a quarter (28%) of the same population add salt at the table. Salted meats and fish like salt-fish and salt-beef, and heavily seasoned meats such as fried chicken, stews and curries can contain a lot of salt.

Dietary advice

By using the advice below, people of black African descent can help to reduce their risk of getting high blood pressure or if they already have high blood pressure, help lower their blood pressure. Remember the daily recommendation is a maximum of 6g of salt per day.

• Sea salt, rock salt and garlic salt are just as bad for your health as table salt and should be avoided
• When cooking, salt should not be added to the water used for cooking vegetables, pasta and rice
• Instead of salt other flavourings such as fresh herbs, spices (but not prepared spice mixes which often contain added salt), lemon juice and wine should be used
• When buying processed foods lower salt alternatives should be chosen
• Look out for words on labels like sodium, salt, brine, cured, pickled, corned, smoked on labels – and only eat limited amounts of these products
• Any salted meat or fish e.g. salt fish, salted mackerel, saltbeef, khobi, salted pigs tail should be soaked in water for 24 hours (changing the water a number of times) to remove most of the salt before cooking. Better still, eat fresh unsalted meat or fish

To further reduce the risk of getting high blood pressure, heart disease and strokes people should make sure they eat at least 5 portions of fruit/vegetables per day, increase the amount of exercise they do (at least 30 minutes, 5 times a week) and reduce the amount of saturated fat they eat. It is important to try and lose weight if overweight, and also to stop smoking.

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References

1. National Statistics (2001). http://www.statistics.gov.uk/cci/nugget.asp?id=273. [accessed 07/07/2010]
2. Ageymang C & Bhopal R. Is the blood pressure of people from African origin adults in the UK higher or lower than that in European origin white people? A review of cross-sectional data. Journal of Human Hypertension. 2003; 17(8). 523-534
3. Cappuccio FP et al. Hypertension and ethnicity: prevalence and level of detection and management in the community in England. American Journal of Hypertension. 1997; 10, 22A.
4. Cappuccio FP. Ethnicity and cardiovascular risk: variation in people of African ancestry and South Asian origin. Journal of Human Hypertension. 1997; 11, 571-576.
5. Primatesta P et al. Blood pressure levels and hypertension status among ethnic groups in England. Journal of Human Hypertension. 2000; 14, 143-148.
6. Lip GYH et al. Ethnicity and cardiovascular disease prevention in the United Kingdom: a practical approach to management. Journal of Human Hypertension. 2007; 21, 183-211.
7. He FJ et al. Importance of the renin system in determining blood pressure fall with salt restriction in black and white hypertensives. Hypertension. 2001; 32, 820-824
8. He FJ et al. Effect of Modest Salt reduction on Blood Pressure, Urinary Albumin and pulse Wave velocity in which black and Asian mild hypertensives. Hypertension. 2009; 54, 482-488.
9. Vollmer WM et al. Effects of diet and sodium intake on blood pressure; subgroup analysis of the DASH sodium trial. Annals of Internal Medicine. 2001; 135, 1019-1028
10. Swift et al. Modest salt reduction lowers blood pressure and urine protein excretion in black hypertensives.  Hypertension. 2005;46:1-5
11. These calculations of reduction in risk for black people of African descent are based on two papers: Prospective Studies Collaboration. Lancet. 2002; 2 The 360,1903-1913 and Vollmer et al. Annals of Internal Medicine 2001; 135 (12), 1019-1028.
12. Health Survey for England- The Health of Minority Groups (1999). http://www.archive.official-documents.co.uk/document/doh/survey99/hse99-07.htm [accessed 07/07/2010]