Which rice is better?

Following the discussion on carbohydrate-rich foods, today’s discussion is all about rice. In particular, we aim to answer the question: which rice is better?

What is rice?

Rice is “the starchy seeds of an annual southeast Asian cereal grass (Oryza sativa) that are cooked and used for food” (1).

Rice belongs to the grains and cereals, alongside bread, pasta, oats, etc. This are also commonly known as “carbs” or “carbohydrates”, even though fruits, vegetables and legumes are also rich sources of carbohydrates.

Although rice originated in Asia, it has spread throughout history to other parts in the world. Many countries, such as Spain and its colonies, Italy and the US have traditional meals in which rice plays an important role. Think paella, arroz con pollo, risotto and jambalaya. In my country, many people are of the opinion that “it’s not a meal if it doesn’t have rice”.

Types of rice

Besides regular rice (i.e. medium grain white rice), other types of rice available in Australia are (2):

Low GI white rice (a.k.a. Doongara rice or clever rice): long grain rice developed and grown in Australia to have a lower glycaemic index (GI) than regular rice.
Basmati rice: long grain rice popular in Indian cuisine, which as a lower GI than regular rice.
Jasmine rice: a fragrant rice from Thailand, which looks similar to Basmati.
Arborio rice: a short and rounder grain rice used in Italian dishes like risotto.
Brown rice: rice that hasn’t had the bran layer removed. As mentioned before, it contains more nutrients (and anti-nutrients) than its white counterpart. It takes longer to cook than white rice and has a chewier texture.
Coloured rice: e.g. black rice and red rice, which contain more phytonutrients than white rice due to their pigments.
Wild rice: technically not rice, but eaten as a substitute. From Merriam-Webster: “a tall aquatic North American perennial grass (Zizania aquatica) that yields an edible grain” (3)

Other well-known types of rice include sushi rice, bomba (used in paella) and carnaroli (used for Italian rice-based dishes.

Nutrients in rice

The data for the next couple of sections come from the Australian Food Nutrient Database (4).

Macronutrients

Rice is very low in fat, and thus low in energy (kilojoules). As you can see in the graph below, rice is rich in carbohydrate and contains a little bit of protein.

Most types of rice (excluding wild rice, which as we saw before is not actual rice) have roughly the same amount of starch and sugar.

Micronutrients

The real difference between different types of rice comes with micronutrients. For example, the outer layer of rice (i.e. the bran) contains most of the micronutrients and fibre. Therefore brown rice has more nutrients than white rice. Unfortunately, it also contains more anti-nutrients (more on this later). This is the argument that proponents of ancestral-style diets use to justify choosing white rice over brown.

The table below shows the difference in selected micronutrient levels per 100g of various types of rice. Notice that brown rice has little more fibre than white rice, but it is not necessarily a high fibre food (1.5g vs 1g per 100g).

Glycaemic index

As with potatoes and sweet potatoes, glycaemic index (GI) is a good factor to determine which type of rice might be better for you. As a reminder, the GI of a carbohydrate-containing food indicates how much it will raise your blood sugar relative to pure blood glucose.

Brown rice and most white rice have high GI, with the exception of Basmati and rice exclusively grown to have low GI (e.g. clever rice). Wild rice is also low GI. Also, cooking rice for longer raises it GI (5). Refrigerating cooked rice will lower its GI (5, 6), as will eating it with protein and/or fat (5).

Refer to the table below for the GI of selected types of rice (5).

Resistant starch

As it happens with regular potatoes, cooking and then cooling white rice raises it resistant starch (RS) content. Remember that RS is a type of fibre that escapes human digestion and serves as fuel for gut bacteria. In one study, scientists found that cooling cooked rice at room temperature for 10 hours raised its RS levels. Moreover, cooling cooked rice at 4°C (refrigerator temperature) for 24 hours and then reheating it raised the RS content even more (6).

Phytic acid

Phytic acid (PA) is a compound present in plant seeds, including rice. This compound can affect the bioavailability of several minerals, including zinc and iron. Processes such as soaking, sprouting and cooking can lower the amount of PA in rice. It’s important to note that PA can also act as an antioxidant (7).

Toxins

Arsenic is a toxic mineral present in rice due to the growing conditions. The actual level of rice varies between different types of rice (e.g. sushi vs Basmati). However, brown varieties will contain more arsenic than white varieties because it accumulates in the bran (8, 9). This is especially concerning when rice bran is used as a main ingredient in processed foods (9). Preparation methods (e.g. cooking in uncontaminated water) can reduce the amount of arsenic in rice.