Raffinose

We are all familiar with the message that it is important to eat our veg, but some veg is famously associated with causing bloating and wind.  The reason brussels sprouts, in particular, have a bad reputation all comes down to a type of sugar called raffinose.

Brussels sprouts on green background

Love them or hate them?

There is no denying that brussels sprouts are considered to be a Christmas vegetable.  You might be happy to eat a plateful, or you might just have one on your plate “because it’s Christmas”.  Maybe you avoid them altogether!  Personally, I like them and I will eat them with other meals too (if we have any frozen I’ll even eat them during other seasons).

Whether or not you like sprouts may be down to your genetics.  A study by Cornwall College in 2011 found that a genetic variation can result in your taste receptors being more sensitive.  This means that only some people can taste the bitterness of sprouts,  caused by a compound called phenylthiocarbamide (PTC).  About half the population has the gene variation.

Brussels sprouts’ benefits

Brussels sprouts are a type of brassica meaning that they are related to cauliflower, broccoli, cabbage.  All of which should feature in our diet daily (well, may be not all at the same time!).  They are packed with nutrients we need for good health.

Brussels sprouts are an excellent source of vitamin C.  They also provide good amounts of:

  • soluble fibre which is important for digestion and gut health, and has been associated with reduced blood sugar and cholesterol
  • vitamin K which is important for blood clotting, and bone health (if you are taking anticoagulant medication such as warfarin be careful not to consume more vitamin K over Christmas than you normally would to avoid complications with your medication)
  • folate – important for red blood cell formation and healthy cell growth and function.  In early pregnancy folate helps to protect against brain and spinal defects in the foetus
  • small amounts of iron, other B vitamins, magnesium, potassium and phosphorus.

Brussels sprouts’ bad reputation

Bloating and flatulence.

This windy problem associated with the vegetable is as a result of not all components being digested before they reach the colon.  In particular, a type of indigestible sugar called raffinose.

Raffinose can be found in brassicas, beans and some other vegetables.  It requires an enzyme called alpha-galactosidase to break it down which humans do not produce.  This means that raffinose passes into our large intestine undigested where it provides many of our important gut bacteria with a feast.  Unfortunately hydrogen, methane and carbon dioxide are side effects of this feast, and hence wind builds up in our gut until we let it out.  Individuals who are prone to problems with bloating, such as IBS sufferers, may prefer to avoid sprouts to reduce the effects of the gas build-up.

And that smell!

This is mainly due to sulfur* compounds.  Again, our gut bacteria deal with these but produce hydrogen sulfide and methyl mercaptan as a result.  It is these gases, released alongside other gases, that give our wind the distinct aroma.

High levels of hydrogen sulfide produced by the gut bacteria may contribute to inflammation within the gut and bowel-related diseases.

Raffinose may not be all bad!

Raffinose may lead to increased amounts of lactic acid bacteria which help to reduce the risk of gut inflammation and ulcerative colitis, potentially reducing the risks posed.  However, due to the potential problems, try to eat brassicas in moderation and in appropriate portion sizes, according to your own gut health status.

Meanwhile, it is believed that the sulfur compounds may have anti-cancer properties.

Greens and the thyroid

Individuals who have hypothyroidism or goitre may need to consider the balance between their thyroid function, iodine intake and brassica intake.  Brassicas contain compounds called glucosinolates that can interfere with iodine uptake.  You may hear this compound referred to as a goitrogen.  It is present in all brassicas, including turnips, rapeseed and mustard seed.  However, as brassicas contain many beneficial nutrients you shouldn’t necessarily avoid them… and the good news is goitrogens are damaged by cooking and can leach out into cooking water.  This means that you can limit your exposure by eating moderate amounts of cooked brassicas.

To help counter some of the goitrogenic effect, ensure you eat good sources of iodine daily, including:

  • iodised salt (this is standard salt in the USA but not in the UK)
  • white fish and scampi
  • dairy milk and yoghurt (check that any dairy-substitute you use is fortified with iodine)
  • eggs.

For more information about the thyroid and its links to the gut, take a look at my post from earlier this year: https://alible.diet/thyroid-gut/

How to prepare and eat sprouts

Eating sprouts in smaller amounts can help reduce the problems while still giving you some of the benefits.  Do you remember the sprout eating competition between the Vicar of Dibley and David Horton?  I don’t recommend it!  One portion of vegetables is about 80g; that is just 8 medium-sized sprouts.

Sometimes the cooking method can affect our enjoyment of the vegetable.  If you don’t like them boiled or steamed, why not try roasting them or adding them to stir-fries?  You could also add some cooked sprouts into a ‘bubble & squeak’ type meal to make them less obvious.

When boiling or steaming sprouts, don’t over do it – they may take less time than you think.  Ideally sprouts should still be firm (not hard) and not soggy.  And, they don’t need the cross cutting in the base.  This helps them to cook and can cause them to become soggy quickly.  The idea of cutting a cross apparently comes from superstition.  It was thought to drive the evil spirits that lurk in the vegetable and cause illness away.  May be those evil spirits were the raffinose!

*the preferred spelling by the International Union of Pure and Applied Chemistry (IUPAC) adopted by the Royal Society of Chemistry.

Important

If you regularly have problems with flatulence, bloating or digestion that you can’t link to specific changes to your diet, please consult your GP to ensure there are no underlying health conditions.

Do not take any nutritional supplements without first checking your medication to ensure they will not interact or interfere with the function of each other.  Take a look at the medicine instructions leaflet, or consult your pharmacist or other appropriately qualified professional.  At Alible Nutrition, I will review your medications as part of my standard practice before making any nutritional recommendations.

Do you need to review your diet to better support your digestion?

If you have gut health issues (and have consulted your gp!) and are ready, motivated and committed to optimising your health, request a call so we can discuss how nutritional therapy could help you to feel more comfortable.

References/Further Reading