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Updated 28 February 2014

Boost your health with chocolate

If you're a chocoholic, you'll be happy to learn that a growing body of evidence suggests that chocolate may be beneficial to health and prevent heart disease, stroke and more.

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At first glance, the title of this topic appears to be a contradiction! How on earth can that sinful food called chocolate be associated with good health? Not a week goes by that I do not receive desperate questions from the public (mainly women), who confess that they are total chocoholics and need advice on how they can kick the habit of wolfing down a slab of chocolate a day. But recently, more than one scientific study of excellent quality (i.e. carried out by reputable researchers, involving very large populations and published in peer-reviewed journals), has indicated that chocolate may not be as bad for health as we have always believed. In fact there is growing evidence that chocolate and cocoa may even be beneficial to health and prevent heart disease, strokes, metabolic diseases and pre-eclampsia.

UK study

In August of this year, Adriana Buitrago-Lopez and her team of researchers at the University of Cambridge published what is known as a meta-analysis in the British Medical Journal. The meta-analysis evaluated the results of 7 previous studies, to assess the association of chocolate consumption and the risk of developing cardiometabolic disorders (cardiovascular disease including coronary heart disease and stroke, diabetes, and metabolic syndrome).

A total of 114, 009 subjects were represented in this meta-analysis and 5 of the 7 studies reported that chocolate consumption had a beneficial effect on the risk of developing the above mentioned cardiometabolic disorders. The highest level of chocolate consumption reduced the risk of cardiovascular disease by 37% and of stroke by 29% (Buitrago-Lopez et al, 2011).

The researchers believe that these benefits may be due to the high content of so-called polyphenols that are found in cocoa products and chocolate. It has been suggested that polyphenols (also found in red wine, ‘bird-resistant’ sorghum grain, etc), make a substance know as nitric oxide more bioavailable in the human body, which in turn may improve the function of the lining of the blood vessels, reduce platelet function and blood clotting, lower blood pressure and high blood fat levels, and reduce insulin resistance (Buitrago-Lopez et al, 2011).

The Cambridge team were quick to caution that these unexpected findings did not represent carte blanche when it comes to eating indiscriminate quantities of chocolate, because the latter also contains high levels of fat and sugar. However, it has been previously pointed out that the primary fat in chocolate, namely cocoa butter may also have a positive effect on heart health.

Swedish Study

Hot on the heels of the UK study, scientists at the Karolinska Institute in Sweden published a paper in the Journal of the American College of Cardiology, on chocolate consumption and risk of stroke in women. Dr Susanna Larsson and her colleagues (2011), studied data obtained from a mammography study of more than 33,000 women, who reported how much chocolate they had eaten in 1997. Over the next decade, 1549 strokes were recorded in the study population. The subjects with the highest chocolate intake (more than 45 g per week) had 2.5 strokes per 1000 women per annum, while the women with the lowest chocolate intake (less than 8.9 g per week) had 7.8 strokes per 1000 women per year. In other words, the women with the lowest chocolate intake per week, were 3.6 times more likely to suffer from a stroke than the women with the highest chocolate intake (Larsson et al, 2011).

Dr Larsson also pointed out that “Chocolate should be consumed in moderation as it is high in calories, fat and sugar. As dark chocolate contains more cocoa and less sugar than milk chocolate, consumption of dark chocolate would be more beneficial.” (Reuters, 2011).

The energy, fat and sugar values listed for Albany bittersweet chocolate (see Table below) per 100 gram in the SA Food Tables (Wolmarans et al, 2010), do not differ significantly from those of milk chocolate, so one can only surmise that dark Swedish chocolate has a lower energy, fat and sugar content than some brands of dark chocolate sold in SA.

Chocolate and pre-eclampsia

An earlier study conducted at Yale University by Triche and coworkers (2008), investigated 2291 pregnant women in the period 1996-2000. The purpose of the study was to determine the association between chocolate consumption and the risk of pre-eclampsia, which is a major complication of pregnancy. The researchers did not only obtain data on the chocolate intake of their subjects from self-reports during the first and third trimesters of pregnancy, but also analysed umbilical cord serum concentrations of theobromine, a compound found in chocolate.

In this population, 63 women developed pre-eclampsia (3.7%) during the study period. Higher levels of theobromine in samples of umbilical cord blood were negatively linked to pre-eclampsia. This indicates that the pregnant women who ate the most chocolate (more than 5 servings per week) were up to 40% less likely to develop preeclampsia than women who ate the least chocolate (less than 1 serving per week) (Triche et al, 2008).

The authors concluded that “Our results suggest that chocolate consumption during pregnancy may lower the risk of pre-eclampsia. However, reverse causality may also contribute to these findings.”(Triche et al, 2008)

It is possible that the beneficial polyphenols in chocolate and their effects on cardiovascular health may also play a role in pre-eclampsia, which is characterised by a dangerous increase in blood pressure during pregnancy. On the other hand, women who ate chocolate during their pregnancies may have been more relaxed which could have had a positive effect on their blood pressure.

Chocolate addiction

All the above mentioned studies appear to have a found a positive effect of chocolate and cocoa on health, but each one of the study leaders has also issued cautions about indiscriminate consumption of this high-energy food. It was also repeatedly emphasised that dark chocolate with a higher cocoa and a lower sugar content, is preferred.

Those individuals who are addicted to chocolate and cannot go a day without eating a whole slab of their favourite food, need to take these warnings seriously. If you keep in mind that most chocolates, including dark chocolate and so-called ‘diabetic’ chocolate, provide approx. 2300 kJ/100 g or 1150 kJ/50 g slab (see Table below), then eating a whole slab a day can be devastating if you are trying to lose weight. 1150 kJ represents 18% of your daily energy requirements if you are an adult woman on a slimming diet! So it is prudent to reduce your chocolate intake to small quantities of say 10g/day, if you are trying to achieve weight loss.

Using artificially sweetened chocolates such as Canderel milk chocolate (see Table below), does save some kJ, but the fat content of 32 g total fat/100g is not very different to the other types of chocolate in the Table. Chocolate coated raisins have the lowest energy and fat contents, because a relatively large percentage of this confectionary consists of dried raisins.

It is of course easy to get hooked on chocolate. Not only does the smooth, creamy mouthfeel tempt us to indulge over and over again, but cocoa and chocolate products contain a range of addictive chemicals such as theobromine, serotonin, phenylethylamine and endorphins.

The best solution to chocolate addiction is to gradually reduce your intake so that you don’t suffer from withdrawal symptoms which will make you turn straight back to chocolate to relieve the cravings. If you are eating a whole slab of chocolate a day at present, try eating one square of chocolate less every second or third day until you are down to 2 squares (10g) per day. In the meanwhile make sure that you are ingesting sufficient low-GI carbohydrates and proteins to sustain the serotonin levels in your brain so that you don’t get depressed and grab a chocolate to "self-medicate"! Also do some aerobic exercise like going for a brisk walk or jogging to produce endorphins to lift your mood and use up some energy.

It is evident that more detailed studies are still required to explain why chocolate and coca products appear to have these beneficial effects on cardiovascular disease including coronary heart disease and stroke, diabetes, and metabolic syndrome, as well as pre-eclampsia. Until such studies have been carried out, we won’t be "prescribing" chocolate to our patients any time soon. However, when eaten in moderation, a piece of chocolate may well do some good.

Table: Energy, total fat, saturated, mono- and polyunsaturated fat, and added sugar content of 100g portions of selected chocolates (Wolmarans et al, 2010).

 

Type of chocolate

Energy (kJ)

Total fat (g)

Saturated fat (g)

Mono-unsaturated fat (g)

Poly-unsaturated fat (g)

Added sugar

(g)

Choc bar

1980

22.5

15.0

5.1

1.4

56.7

Choc-coated nuts

2422

38.2

15.0

16.0

5.4

37.9

Choc-coated raisins

1861

15.6

9.1

4.8

0.8

27.1

Choc, dark, bittersweet, Albany

2300

30.5

17.7

9.7

1.3

58.8

Choc, diabetic

Brand not specified

2285

32.8

    N/A

N/A

N/A

45.4

Choc, Canderel milk choc bar*

1884

36

N/A

N/A

N/A

N/A

Choc, milk

2302

30.6

18.0

9.6

1.5

54.2

Choc, KitKat

2152

26.6

13.8

9.7

1.6

54.5

 

N/A = Values not available.

* Canderel Website (www;canderel.co.za/our-range/original/chocolate )          

References

(Buitrago-Lopez A et al. 2011. Chocolate consumption and cardiometabolic disorders: systematic review and meta-analysis. BMJ, 343:d4488;  Larsson S et al. 2011. Chocolate consumption and risk of stroke in women. J Am Coll Cardiol, 58(17):1828-9; Wolmarans P et al. 2010. Condensed Food Composition Tables for South Africa. MRC, Parow Valley, Cape Town; Triche EW et al. 2008. Chocolate consumption and reduced likelihood of preeclampsia. Epidemiology, 19(3):459-64; Reuters. 2011. Chocolate can be healthy. Pretoria News, 16 October 2011.)

Read more:

Dark chocolate good for the heart
Chocolate lovers have fewer strokes
Chocolate crisis looms

Dr Ingrid van Heerden is a registered dietician and holds a doctoral degree in Nutrition and Biochemistry. She believes that "we are what we eat" and offers free nutrition and weight loss advice via her DietDoc service on Health24.com. Read more of her articles.

 
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