I was told by my Grandmother that most things which taste super good are bad for you. There is even a Chinese proverb (苦口良药: good medicine is bitter to the mouth) to validate her claim.
So, what about chocolate?
There are not too many children or adults I know, who dislike chocolate. We usually associate chocolate with “delicious”, “sweet”, “treat”. Is chocolate “too yummy to be healthy”?
Surprisingly, it’s not all bad news. In fact, a number of health benefits have been attributed to chocolate across history, including moods, neurocognition, gut inflammation, immunity (Scholey & Owen, 2013; Sokolov et al., 2013; Magraone et al., 2017). A 2018 review of systematic reviews and meta-analyses concluded that, “there is weak evidence to suggest chocolate consumption may be associated with favourable health outcomes” e.g. protective against heart attack, stroke, type II diabetes (Veronese et al., 2018).
Theobroma cacao (also known as the “food of the Gods”, cacao beans, cocoa beans) is the raw material from which chocolate is produced (Wickramasuriya & Dunwell, 2018). In this natural form, chocolate tastes bitter and unpleasantly dry. So not surprisingly, the least processed forms of chocolate provide the most health benefits. The process involved in chocolate making, significantly reduces the health-promoting constituents e.g. polyphenols such as epicatechin, and catechin, and methylxanthines such as caffeine and theobromine (Wickramasuriya & Dunwell, 2018).
Chocolate in its pure form and chocolate with at least 70% cacao, generally contains more health-promoting constituents than more refined types of chocolates e.g. milk chocolate, white chocolate or other chocolate confectionery.
Potential oral health benefits of cacao bean and dark chocolate, have been explored:
Cacao bean husk has been shown to provide antimicrobial effects. Its antimicrobial effects have been attributed to its unsaturated fatty acids e.g. oleic acid and linoleic acid, and epicatechin polymers (Osawa et al., 2001; Matsumoto et al., 2004).
Dentally, cacao bean husk extract has been demonstrated to suppress the growth rate and virulence (by inhibiting bacteria glucan production through its anti-glucosyltransferase activity) of decay-causing bacteria in rats (Ooshima et al., 2000a). However, the same researchers also concluded that the “anticaries (anti-decay) activity is not strong enough to suppress significantly the cariogenic activity of sucrose” (Ooshima et al., 2000b).
A 2011 study published in the European Archive of Paediatric Dentistry compared twice daily use of 0.2% chlorhexidine mouthrinse with 0.1% cacao bean husk mouthrinse in children and concluded that they have similar antimicrobial properties against Streptococcus mutans (a key decay-causing bacteria) (Venkatesh Babu et al., 2011). However, the paper did not discuss if 0.1% cacao bean husk mouthrinse is effective in preventing dental decay.
Theobromine and caffeine are methylxanthines (a type of alkaloid), both are found in cacao beans and chocolate. Theobromine has been explored as a remineralizing agent and an alternative to fluoride (Kargul et al., 2012; Amaechi et al., 2013). Amaechi and co-workers compared remineralization produced by theobromine, fluoride toothpaste and artificial saliva in vitro using a pH cycling model to simulate the human oral environment and found that theobromine and fluoride toothpaste have comparable remineralizing potential (Amaechi et al., 2013). However, it is important to note that in this study, the demineralization and remineralization buffer containing fluoride were used across all test groups – so one must ask the question, is the remineralization effect from fluoride or from theobromine or from both, and how do you determine what the actual effect from theobromine alone would be?
In another study, 200mg/L of theobromine demonstrated significantly greater enamel surface protection of extracted human molars than 100mg/L theobromine in vitro (Kargul et al., 2012). However, applying these results may be difficult, as the high concentrations of theobromine used in the study would be difficult to extract from natural sources at a reasonable price (Franco et al., 2013).
Yet another inviro study concluded that “theobromine did not demonstrate anti-caries benefits, in the presence or absence of fluoride”. (Lippert, 2017)
Theobromine toothpaste is commercially available. The company claims that their patented Rennou (active ingredient: theobromine) exert remineralizing effects by increasing the size of the surface minerals on enamel based on in vitro and animal studies. No clinical trials on the anti-caries effects of theobromine in humans are available as yet. Researcher, Dr Nakamoto is one of the founders.
The levels of catechin and epicatechin in chocolate are high. Catechin and epicatechin are flavonols (a form of polyphenols) that exert anti-oxidant and anti-inflammatory benefits, disrupt bacterial glucan formation, and promote protective gut flora in a similar way as prebiotics and probiotics (Franco et al., 2013; Ren et al., 2016).
Calcium and vitamin D
Chocolate also contains calcium and vitamin D. The benefits of calcium and vitamin D to bone health, and in enamel and dentine formation during tooth development are well recognized. Calcium ions in the oral environment are important for maintaining oral balance, promoting remineralization and reducing demineralization. The role of vitamin Din preventing dental decay is not so clear (Hujoel, 2013). However, children with vitamin D deficiency tend to have higher rates of dental decay (Schroth et al., 2016; Wojcik et al., 2019). Some recent studies investigating how vitamin D contributes to tooth protection have suggested mechanisms relating to antibacterial properties and effects on the oral microbiota (Gyll et al., 2018).
Availability and concentration of health-promoting constituents
Unfortunately, chocolate that have been modified to taste great, generally have large amounts of added sugar, reducing the teeth friendly-nature of “real chocolate”.
To provide protective effects for our oral health, the health-promoting constituents in chocolate have to be available in high enough concentrations in the mouth, especially in the presence of acids, sugars, enzymes and microbes.
Lollies or chocolates?
Having said that, when comparing the decay-causing risk of plain milk chocolate vs. lollipops, gummy bears or other flavoured candies, milk chocolate is the slightly better option.
Why? Although both chocolate and candy are high sugar foods, milk chocolate contains calcium and antibacterial constituents, is not acidic and is less sticky, compared to plain sucrose, jelly bean or flavoured candy. A small study by Prof Monty Duggal noted that diet chocolate (containing sugar substitute) was least acid-promoting than other types of chocolate, and that sugar containing chocolate with at least 20% cocoa had less acid-promoting potential than sucrose (Verakaki & Duggal, 2003). More recently, probiotic containing chocolates have been tested (Janani et al., 2019). The results demonstrated that all probiotic containing chocolates were less acids-promoting than non-probiotic containing chocolates. Additionally, the researchers noted that plain dark chocolate was less acids-promoting than plain milk chocolate and plain white chocolate.
The presence of sour (acids), sweet (sugars) and sticky (reduced clearance) in the one food or drink creates chaos in oral balance (especially the natural remineralization-demineralization balance). Acids result in demineralization and soften the surface of enamel which further exacerbate demineralization. Sugars lead to formation of acids by bacteria in the mouth and contribute to demineralization. Stickiness facilitates retention and allows acids and sugars to create more damage in the mouth over longer periods of time. Frequent consumption of 3S (sour+sweet+sticky) food / drink ultimately leads to irreversible teeth damage…more speedily and more severely.
So, is chocolate good for teeth? Well, can’t really call chocolate a tooth-friendly food just yet, but it’s definitely better than a sticky lollipop or chewy gummy candy!
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