Wednesday, April 21, 2010

Practically Paleo Perspective: Rice

A commenter asked me for my opinion on rice, so here you have it.

[Updated 4/20/12:  The original version of this post illustrates some of the poor reasoning I fell into as a result of reading books and blogs by people advocating paleo diet, while ignoring the bulk of research on diet and health.  My critiques and corrections of the original appear in brackets.]

Botany and Antinutrients

Rice is the seed of a monocotyledonous plant known to botanists as Oryza sativa. 

Like other seeds, whole (brown) rice contains chemical defenses against predation, primarily present in the hull and bran of the seed.  They include phytin (phytate), trypsin inhibitor, oryzacystatin and haemagglutinin-lectin.

Phytate binds minerals including calcium, zinc and iron; it also binds with protein.  Heat (cooking) does not denature phytate.  Studies have found that subjects fed brown rice diets have poorer mineral balance when compared to subjects fed milled rice diets.  On the other hand, phytate protects against dental caries, so white rice promotes dental decay more than brown rice.

[4/20/12:   Phytate fears are not founded on good science.  Science does not support claims that dietary phytate causes harm to humans.  Humans adapt to phytate ingestion, dietary vitamin C cancels the negative effect of phytate on mineral absorption, phytate adversely affects mineral balance only if the diet is deficient in minerals, and research has shown that dietary phytate has a strong health benefits for prevention and treatment of cardiovascular disease and cancer; it even inhibits the growth of malignant tumors.]

Trypsin inhibitor occurs in rice bran.  Steaming rice bran at 100 degrees C (212 F) inactivates trypsin inhibitor.  [4/20/12:  This means that boiled brown rice has no active trypsin inhibitor.] Polishing rice eliminates trypsin inhibitor.

Haemagglutinins  or lectins consist of globulins that agglutinate mammalian red blood cells and precipitate glycoconjugates or polysaccharides. Lectins bind to specific carbohydrate receptor sites on the intestinal mucosal cells and thus interfere with the absorption of nutrients across the intestinal wall.  Rice lectin agglutinates human A, B and O group erythrocytesAccording to the FAO, rice lectin sharply loses activity when heated to 100 degrees C. [4/20/12: Hence, since we boil rice at 100 degrees C before eating it, we don't have to worry about this lectin.]

Oryzacystatin is an inhibitor of protein-digesting enzymes.  Oryzacystatin remains 100% active after at least 30 minutes of boiling.

Rice also contains an allergenic protein that occurs primarily in the milled rice, not the bran, and remains stable (60%) even after boiling for 60 minutes at 100 C (212 F).

[4/20/12: Rice allergies occur in only 10% of atopic patients in Japan and less in Europeans and Americans.  Compare this to beef allergy:

"The prevalence of beef allergy is between 3% and 6.5% among children with atopic dermatitis and can be up to 20% in cow's milk allergic children. Several studies reported an incidence of 1-2% of food-induced anaphylactic reactions caused by ingestion of beef. In another study an even higher figure of 9% of anaphylactic events from foods were induced by beef."
These data appear to indicate a much greater incidence of anaphylactic events triggered by beef than by rice.]
 
Nutritional value

Rice has a very high carbohydrate content and low levels of micronutrients compared to vegetables or fruits.  The following table compares the levels of selected vitamins and minerals in 50-kcal portions of brown rice and a selection of vegetables and fruits.  Red numbers indicate items with the highest levels among the foods compared. Click on image to see larger version.



Notice that brown rice does not have the highest level of any of the nutrients listed.  White potatoes have twice as much riboflavin (B2), 2.5 times as much folate, vitamin C not present in rice, 10 times more potassium, more than 3 times as much iron, and 25% more calcium than brown rice.    Sweet potatoes supply carotenes (provitamin A) and vitamin C not present in brown rice, three times as much B2, 5.5 times as much folate, 9 times as much potassium, slightly more iron, and more than 3 times as much calcium.  Winter squash also makes brown rice pale in comparison.

Strawberries have 10 times as much B2, 12.5 times as much potassium, nearly 3 times as much iron, and more than 5 times as much calcium.

No matter which vegetable or fruit you compare to brown rice, you find the vegetable or fruit makes brown rice pale in comparison.

Then if you compare brown to white rice:


Brown Rice vs. White Rice

Nutrient
Brown Rice (1 cup)
White Rice (1 cup)
Energy (kcal)
218
241
Protein (g)
4.5
4.4
Carbohydrate (g)
46
53
Fat (g)
1.6
0.4
Fiber (g)
3.5
NA
Thiamin (mg)
0.2
0.3 (synthetic)
Riboflavin (mg)
0.02
0.03 (synthetic)
Niacin (mg)
2.6
2.8 (synthetic)
Pyridoxine (mg)
0.29
0.11
Folacin (mcg)
7.8
109.8 (synthetic)
Calcium (mg)
19.5
1.9
Iron
1.0
2.7 (fortified)
Magnesium
86
15
Phosphorus
150
61
Potassium
154
48
Zinc
1.2
0.74

Laying aside the synthetic fortification, brown rice supplies nearly 3 times as much pyridoxine, 10 times as much calcium, almost 6 times as much magnesium, more than 3 times as much phosphorus, more than 3 times as much potassium, and almost twice as much zinc.  Therefore, white rice doesn't hold a candle to brown rice, and brown rice doesn't hold a candle to white potatoes.

[4/20/12:  Turn this around, and judge by energy, protein, and carbohydrate delivery per unit volume, and you find that brown rice surpasses non-starchy vegetables and fruits.  We need some foods for energy and macronutrients, and some foods for micronutrients.  Brown rice is a nutrient-dense starch and energy source compared to white rice.]

White or brown, rice is basically filler with little nutritional value compared to vegetables and fruits.  If you eat rice, you crowd out more nutrient-dense sources of carbohydrate. 

[4/20/12:  Wow, what a ridiculous argument!  Both brown and white rice are much more nutrient-dense than fats like butter, lard, and olive oil, so I would have been more correct to state that fats are fillers compared to brown rice.  When I compared the micronutrient content of two equicaloric diets, one high in meat and supplying most of its energy from fat, and the other low in meat and supplying most of its energy from starches like brown rice, the starch-based diet won hands down.]

Ecology

Environmentalist vegetarians like to blame livestock for global warming, but according to Wikipedia:

In many countries where rice is the main cereal crop, rice cultivation is responsible for most of the methane emissions....Methane is twenty times more effective as a greenhouse gas than carbon dioxide.
[4/20/12:  This is an example of the half-truths used to support paleo perspectives.  How about taking a look at relative contributions of rice compared to animal products?  A study published in the American Journal of Clinical Nutrition calculated the amounts of greenhouse gases (carbon dioxide, nitrous oxide, and methane) emitted in the production of 22 different commonly consumed foods, in kg of CO2 equivalents per kg of final product:   Rice, 1.3;  eggs, 2.5; rapeseed oil, 3.0; chicken, 4.3; cod, 8.5; pork, 9.3; cheese, 11; beef, 30.  So the favored foods of low carb and paleo diets produce 2 to 23 times as much greenhouse gas emissions as rice.]

Further, rice fields are the principal breeding grounds for mosquitos that carry malaria.

So there you have my perspective on rice.   I do not recommend regular consumption of either brown or white rice. [Line through added on 4/20/12.]

[4/20/12:  I now highly recommend eating rice and other grains as staple foods, and I no longer recommend eating eggs, poultry, fish, pork, or beef or beef products.  Grains are far superior to meats and fats as human energy sources and for health support, and have much less deleterious effect on the environment.  Science has shown us that meat- and fat-based paleo dieting is not beneficial to human health, animal welfare, or for ecosystem preservation.]

28 comments:

John said...
This comment has been removed by the author.
Dustin C said...

Let’s not forget about trematodes breeding in the rice fields. Blood flukes (schistosoma) cause plenty of problems for rice farmers amongst others living in South East Asia (and other areas).

I still love white rice cooked in coconut milk, nice treat here and there.

Greg said...

Great overview- I came to the same conclusion on potato vs rice for nutrients, but still wanted to learn more about their anti-nutrients.

Do you speculate that rice has anything to do with the perceived better health of Asians? Not as bad as wheat?

Beulah said...

I went gluten-free for three years. Though there were some initial improvements in my health (which may or may not have been related), none of the symptoms I was hoping to address improved long-term, and several got far worse, such as my eczema.

I'd always heard that rice was hypoallergenic, but a recent two-week experiment eating germinated brown rice brought on the beginnings of a familiar itchy rash on my cheeks that had disappeared in recent years, since going to a more WAPF-type one, where I ate bread if sourdough and didn't eat much rice. (This is bread consumption is past-tense as of two weeks ago).

Aha! Brown rice. Not so good for me after all, and you've showed me some other good reasons why, aside from a suspected allergy.

Unfortunately, I also seem to be hypersensitive to the solanine in potatoes - they give me very achy joints. I'm kind of bumming here and getting tired of sweet potatoes, fast.

mikoro said...

If I need a high carb source, what would you suggest?

Ned Kock said...

Very good points Don.

By the way, the glucose response to brown and white rice is about the same. Both are very similar to the response to white bread. See top part of Table 4, on the post below:

http://healthcorrelator.blogspot.com/2010/04/insulin-responses-to-foods-rich-in.html

The table also gives the insulin response to those foods, which is not that high (with exception of white bread).

Katherine said...

Potatoes sound like a smarter high carb source mikoro.

A similar analysis of legumes would be great, specifically black beans which have a better "reputation"

Don said...

John,

Thanks.

Dustin,

Thanks for that info.

Greg,

Wheat lectin has insulin-like properties plus gluten is pretty toxic even to non-celiacs.

Beulah,

People commonly/erroneously believe rice is not allergenic. When I eat it I get abdominal bloating.

Matthew said...

Interesting post and information, however:

Phytates can be broken down by soaking/fermentation.

Tripsin inhibitor would be eliminated and lectins greatly reduced by normal (30 min) cooking of brown rice in water.

Oryzacystatin is not degraded but does not have a impact on trypsin or pepsin. Also rice is not usually consumed for its protein content.

Allergies are very individual and are also occur for foods like eggs, nuts and seafood. I have never notived any effects to eating rice.

I agree that brown rice is not a particularly nutrient dense food but I think if it causes no negative effects there are many worse choices to make.

Your blog is always a very interesting read.

PrimalHomemaker said...

Thanks for the great info on rice. The only time I really miss it is when I am eating sushi.

Your blog is a great resource with amazing info.

Thanks,
Wendee from http://www.primal-homemaking.com

Anna said...

Amen.

Rick said...

You can use cauliflower ground up in a food processor and then steamed for five minutes as a passable rice substitute.

Gabriel said...

There is something about rice as a staple that is advantageous over wheat or corn, or at least I have gleaned so from my personal observation.

Perhaps it has something to do with allergenicity. Wheat and corn probably leave more of a residue from digestion, even when properly prepared according to WAPF guidelines of traditional grains.

I continue to use rice as a fallback to potatoes and other tuberous starches. It is less nutrient dense, but I find white rice to be a clean burning fuel when I need calories fast.

However there is something about it that is addictive, like when I go to a Chinese restaurant and just can't stop eating it.

wozza said...

In your post of 17/6, you list brown rice as the first starch you eat. What gives?

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Rhonda Lynn Hardey said...

Did you mean phytate promotes dental caries, so white rice promotes dental decay more than brown rice? You said phytate protects against dental caries, so white rice promotes dental decay more than brown rice.

phil said...

I love this blog. If you have celiac i personal dont think it would be recommended to eat rice but govement and docs tell people to munch them down not informing people that GREASS SEEDS arnt the way forward.

Please if anyone has more info on celiac not or to eat rice please blog back

elegantsharen said...

Since you don't recommend either white or brown rice, what do you think of wild rice (which I have read is a grass) or black rice?

elegantsharen said...

Since you don't recommend either white or brown rice, what do you think of wild rice (which I have read is a grass) or black rice?

Don said...

Elegantsharen,

Actually I changed my views. I recommend brown, black, or wild rice.

Rex said...

Don, why have you recently changed your views regarding brown rice? Care to do a post in the near future?

Don said...

Rex,

I updated the post to give some of the reasons I have changed my views, and to illustrate how far paleo-inspired fears of grains and praise of meats and fats can lead one astray from reality.

Rex said...

Don, Thanks for that excellent post. Very nice summary of some of the research into this topic. I have been trying to navigate the diet puzzle for some time now, and I was initially very convinced by the WAPF/paleo argument that humans are designed to eat mainly animal products, specifically organ meats and fat, and some vegetables, fruits, and nuts as supplements. Given all the anthropological/ethnographic research on this topic, the argument for consuming this kind of diet seemed very, very convincing.

The problem was that it did not square with what I experienced while living in southwest China for 3 years: older Chinese people eating a traditional diet based on grains, legumes and vegetables with supplementary animal products, fruits, and nuts were very healthy, and obviously had excellent genes.

I now think the traditional rural Chinese diet is the way to go, but I disagree that meats are never beneficial. There is a lot of evidence that small-moderate consumption of quality meat is healthy, and traditional Chinese diets do include animal products. Fats are a structural element, and we need omega-3's and 6's. Fat soluble vitamins are likewise important, and eating loads of pro-vitamin A is not the same thing as eating liver. Your thoughts?

Don said...

Rex,

"There is a lot of evidence that small-moderate consumption of quality meat is healthy,"

A lot? Would love to see that.

"...and traditional Chinese diets do include animal products."

Its a long way from "is" to "ought."

Fats? There are only two essential fatty acids, linoleic (-6)and alpha-linolenic (-3), both of which occur in plant foods in larger amounts than in meats. A single teaspoon of flax seed oil will cover requirements. Current evidence does not support idea that DHA is an essential dietary fat.

The body makes most structural fats as needed.

Fat solubles include A, D, E, K.

VT-D we can get from sun and meats other than fish are not good sources anyway. One would have to eat a rather large amount of fish (1+ pounds daily) to get anywhere neer adequate D nutrition. Sun is far more efficient.

E is produced by plants primarily provided by nuts and seeds.

K also produced by plants or microbes and abundantly supplied by plant foods (K2 is NOT a dietary essential).

Studies show that people eating little or no preformed A strongly convert carotenes into retinol. Consequently, the Institute of Medicine does not consider retinol (the VT-A in animal products) an essential nutrient.

B12 is produced by microbes. The most efficient way to get it is a supplement, which the Institute of Medicine recommends to all people 50 years of age and older anyway, regardless of meat intake.

I think it is not possible to support scientifically a requirement for meat.

Chinese diets also are based largely on white rice. Eating animal flesh is like white rice taken as a symbol of wealth, something Chinese strive for. That doesn't translate to nutritional necessity or benefit, any more than the fact that the Chinese prefer white rice means that white is a superior nutritional choice to brown rice.

Rex said...

Don, Thanks for the reply. Lots of good information there. Since it’s so easy to get lost in the ocean of often conflicting nutrition data, I think it’s best to use TCM as a starting point for dialogue and future research on diet. TCM is based on thousands of years of empirical evidence, and unless I’m mistaken, it states that animal products may be beneficial for certain individuals and in certain circumstances. Animal products are not strictly required according to TCM, but I think it’s important to keep in mind cultural context in this case. In my limited point of view, China is a very populous country, and the only way to keep everyone fed and healthy within the limits of what was feasible and practical at the time would have been to promote a vegetarian diet as far as possible. I believe that you can get away with veganism as long as you know what you’re doing (many do not), TCM and Ayurveda both support this, but is it ideal for human health? That’s the question I would like to answer!

Chinese people do not consume animal products only as symbols of wealth. After living in China for 3 years in both cities and rural areas, I can assure you that farmers and the poor consume animal products even when it’s not a special occasion and no one is watching. Why do they keep doing it if it truly is totally unrequired as you say it is? For sensual pleasure or because they believe it’s good for them?

Regarding fats: I have a few concerns. 1) Are plant fats as efficiently absorbed and metabolized as animal fats? 2) Are plant fats in the ideal proportions/ratios for human beings? DHA may not currently be considered an “essential” fat, and just because vegans can get away with not consuming any, doesn’t mean it isn’t beneficial.

I agree the best source of vitamin D is the sun. It probably doesn’t hurt to up your consumption of fatty fish/lard in the dark of winter though…

E is provided by plants, but also by organ meats.

According to this well-cited article, http://www.westonaprice.org/fat-soluble-activators/x-factor-is-vitamin-k2, K2 is required above and beyond K1 for skeletal health among other things.

According to another well-cited article, http://www.westonaprice.org/fat-soluble-activators/vitamin-a-on-trial, carotenes are not synonymous with adequate retinol.

B12 is found extensively in animal products, and supplements may not be adequate. Deficiencies take decades to develop sometimes. Why take the risk? Just eat some meat once in a while.

I know that you have abandoned “paleo” aka a high-fat, low-carb diet, but I disagree that we should jump to the opposite extreme. I do not think the evidence from anthropology, evolutionary biology, and ethnographic studies should be totally ignored. Primitive HG groups around the world include animal products in their diet. Additionally, unless I’m mistaken, the current hypothesis is that it was Homo sapiens’ consumption of animal fats/organs that drove our phenomenal brain growth 2.5 million years ago. Do you really think that plants were responsible for this evolutionary change? It seems to me that a plant based whole foods diet that uses brown rice for energy, and judicious use of vegetables, fruit, nuts, seeds, and animal products for nutrition and balance according to individual constitution and requirements comprises the best of both worlds and is supported by both TCM and modern science.

EricaDavid said...

Any thoughts on why I seem to be able to tolerate brown (and white) rice with no problem but products made with brown rice flour make me feel awful (bloating, nausea). I see that lectins are reduced with heat but breads made with rice flours are baked in a hot oven and rice chips are fried in hot oil so I can't figure out why I'm sensitive to rice flour. Maybe I should try white rice flour.

apelila said...

Don

dude.. How tragic.
You swung from one side to the other, lol.
Maybe you just need to get in the middle until you can grow your backbone strong enough to support yourself.