Tuesday, July 14, 2015

Cutting Calories in Rice

Reader Gillian Street alerted me to a news item suggesting that we had found a way to reduce the energy (Calories/kilojoules) in rice by 10%, and possibly by as much as 50% soon, and this would result in a “healthier rice”. Immediately I was sensing a headline and not a story. Why?

Creating resistant starch
Researcher Sudhair James reported at a conference that if you added coconut oil to simmering rice, then chilled the rice for 12 hours after cooking, the proportion of resistant starch increases.

To make sense of this first we need to know what is resistant starch (RS). We don’t digest all of the starch in food. Some of it is in a form that is resistant to digestion, hence the term. The undigested starch then goes into the large bowel to be consumed by the resident friendly bacteria. This is good, being the main role of dietary fibre too. Foods such as breads, pasta, legumes, bananas, potatoes and corn chips all provide a reasonable amount of RS.

RS benefits
We already knew that if you cool cooked rice, pasta and potatoes that the level of resistant starch rises, meaning that you digest less starch in a cold rice, pasta or potato salad than in hot stir-fried rice, spaghetti marinara or baked potatoes. The cooled starch becomes less soluble and harder to digest.

What are the potential benefits of RS? It helps lower the Glycemic Index of a meal, has a laxation effect, increases the satiety of the meal, and as the healthy bacteria in your large bowel chew through the RS they produce acids that protect the bowel lining, reducing the risk of bowel cancer. Pretty cool eh?

10% fewer Calories
OK, back to the rice story. Sudhair James’ cooking method reduced the kJs by about 10%, which is quite minor in the scheme of things. Why not just eat a little less rice or, even better, not eat that biscuit or pastry for morning tea, or not buy the Maltesers at the movies, or the cake with coffee. It’s quicker, easier and more effective than going through the cook-add-oil-chill-for-12-hours-then-microwave process of saving a few Calories. A cup of steamed rice is 960 kJs (230 Cals) so a 10% saving is 96 kJs (23 Cals) or about one-third of a chocolate biscuit. Get my drift?

Maybe a company will produce rice that has been pre-cooked with oil and dried before putting a packet, but a reduction of 10% kJs would have a net result of zero when it comes to body weight, in my opinion.

OK, but what if they get up to a 50% cut in kJs, wouldn’t that shatter the earth in some manner? Yes, I suppose so, but that is purely speculative for the sake of the story, in my view.

What does it all mean?
Right now we eat an average of 5g of resistant starch each day, yet our goal should be closer to 20g. A rice with more RS could have potential health benefits, no doubt. My guess is that it will come at a premium cost, and may even cause some gut discomfort with all that RS being eaten by bacteria creating gas as a by-product. In the meantime, I suggest you do something radical, yet exceptionally dull, which is to eat regular rice and serve with wholesome plant-based foods and maybe a little meat. No way that will get you a headline.

Kefir 2: made using grains and water

Alberto Gómez from Buenos Aires asked about kefir. He very politely pointed out that I had misunderstood his question about using kefir as a sports drink. So he wrote:

“When I mentioned that kefir could be used as an isotonic drink, I was referring to the kefir prepared with water, not milk. The way to prepare it is to have three spoons of kefir grains, a litre of filtered water, three spoons of brown sugar, a lemon split in halves and three dried plums or dates. You put all of them in a glass container leaving enough air on it and they cultivate in 1-3 days. I do it in two days.

Every day you have to stir the mix. After the time is over, you filter the mix, reuse the kefir grains which amount has increased (separate a portion and use the right proportion, the unused grains could be kept in the fridge for several days keeping them in water with sugar), squeeze the lemon and if you want some fizz just leave the juice in a tight recipient for few hours, put it on the fridge and...voilá!!! you have the isotonic beverage.”

One additional comment from Alberto: “Kefir grains for milk and water are not the same, they share same origin but are different. Advantage of kefir prepared with water is that there are no limits for consumption, the one prepared with milk is heavier and should be consumed with moderation.”

Let me add that I’m still using my milk-based kefir on my cereal in the morning. Adds a pleasant tart sweetness to the start of my day. Thanks again Alberto.

Vitamin D in Mushrooms

I work for the mushroom industry in Australia and very recently we did something not yet done anywhere else that I know of. I arranged a collection of retail mushrooms from a range of stores in five capital cities and had them sent to the National Measurement Institute in Melbourne for analysis of their vitamin D content.

First, I should say that mushrooms are the only non-animal food to naturally produce vitamin D. Just like you, they do it in response to exposure to a source of UV light (eg sunlight). Mushrooms labeled “Vitamin D Mushrooms” have at least the daily needs of D in a serve (10 mcg), because they are exposed to UV light post-harvest.

What surprised me is that regular retail mushrooms have 20-25% of your daily D needs. I suspect that they are producing D from the UV bandwidth in the fluorescent lights in-store.

Table. Vitamin D content of store-bought button mushrooms (100g)
Vitamin D mcg/100 g serve
Regular retail mushrooms (sliced & whole)
Cooked regular mushrooms
Regular mushrooms after 1 hr in the winter sun
Vitamin D labelled mushrooms
Cooked Vitamin D labelled mushrooms
Source: National Measurement Institute

Following the strict protocol set by Food Standards Australia New Zealand, the resulting data was placed on their website. From there you can download the report.

It is winter in the southern hemisphere as I write and about half the population in Australia and New Zealand (and probably Argentina, Chile and South Africa) will be vitamin D deficient. Mushrooms can be part of the solution.