It has long been thought in Paleo circles that white rice—if consumed as part of a Perfect Health Diet styled Paleo (Paleo + starch as white rice)—is basically just a means of providing carbohydrate but not really much of anything else.
Though it's fine to get a reasonable amount of starch carbage (30% of kcal daily is a good mark) via something that's actually food-like, I think it's not quite accurate to dismiss potential real health benefits to rice: parboiled rice.
Here's from the Wikipedia article:
Parboiled rice (also called converted rice) is rice that has been partially boiled in the husk. The three basic steps of parboiling are soaking, steaming and drying. These steps also make rice easier to process by hand, boost its nutritional profile (other than its vitamin-B content, which is denatured) and change its texture. About 50% of the world’s paddy production is parboiled. The treatment is practiced in many parts of the world such as India, Bangladesh, Pakistan, Myanmar, Malaysia, Nepal, Sri Lanka, Guinea, South Africa, Italy, Spain, Nigeria, Thailand, Switzerland, USA and France. [...]
Parboiling drives nutrients, especially thiamine, from the bran to endosperm, hence parboiled white rice is 80% nutritionally similar to brown rice. Because of this parboiling was adopted by North American rice growers in the early 20th century.
The starches in parboiled rice become gelatinized, then retrograded after cooling. Through gelatinization, alpha-amylose molecules leach out of the starch granule network and diffuse into the surrounding aqueous medium outside the granules which, when fully hydrated are at maximum viscosity. The parboiled rice kernels should be translucent when wholly gelatinized. Cooling brings retrogradation whereby amylase molecules re-associate with each other and form a tightly packed structure. This increases the formation of type 3-resistant starch which can act as a prebiotic and benefit gut health in humans. [emphasis added]
OK, that takes care of a couple of the items, higher nutrition and more resistant starch. But how about glycemic index? Here's a source, but there are many.
Parboiled rice has double the fiber than you'd get from cooked white rice. It has a low glycemic score of 38, compared with a high 89 for white rice, notes Harvard Health Publications. A low glycemic score indicates that the carbohydrates in parboiled rice do not cause a large spike in blood sugar. [emphasis added]
That right there is good evidence that the resistant starch levels are higher, since we have so manny anecdotes of blood glucose blunting by taking potato starch sometime before or with a meal. RS slows digestion, so you're getting about the same amount of carbs, just over a longer period of time.
Mark Sisson even highlighted the interesting aspects of parboiled rice as compared to brown and white back in this 2010 post: How Bad is Rice, Really? Of parboiled rice, he writes:
Parboiled rice is interesting. Parboiling involves partially boiling the intact rice seed – husk, bran, and all. This, in theory, is supposed to incorporate some of the bran’s nutrients into the interior. The parboiled rice is then dried and milled, producing a white rice with greater nutrient content than regular white rice. How does it pan out? A 100g raw dose contains:
- 81 g carb
- 2 g fiber
- 1 g fat
- 7.5 g protein
- 0.224 mg thiamin
- 5 mg niacin
- 0.74 mg iron
- 27 mg magnesium
It kinda works. There’s very little mineral change from white rice (perhaps even a reduction), but some of the vitamins seem to increase by parboiling. Interesting.
Yep Mark, indeed it is. One thing I was not able to find was a source for phytic acid levels in parboiled rice, compared to brown rice or plain polished white rice. Perhaps someone can dig that up if available and drop it in comments.
Update: I should mention that I also typically increase the nutrition even further by cooking it in the rice cooker with Kitchen Basics chicken stock. Two cups of Uncle Ben's Original Parboiled rice to a 1-quart container of the stock. Leftover rice goes immediately into the fridge for cooling and to later make my now favorite fried rice dish: Chicken Fried Rice, Filipino Sinangag (Garlic Fried Rice) Inspired.