Is Niacin Found in Rice? A Guide to B3 in Your Grains

December 16, 2025 •

4 min read

While severe niacin deficiency is rare in many developed countries, it was once a serious public health concern, particularly in populations relying heavily on unenriched grain diets. This fact brings to light an important question: is niacin found in rice and in what quantities?

Quick Summary

The niacin content in rice varies significantly depending on how it is processed. Brown rice has more natural niacin, but much of it is poorly absorbed. White rice is low in natural niacin but is often fortified for added nutritional value.

Key Points

Niacin is found in rice, but amounts vary: Brown rice naturally contains more niacin than unenriched white rice, but enriched white rice has niacin added back.
Processing reduces niacin: The milling process that turns brown rice into white rice removes the bran and germ, which contain most of the natural B vitamins, including niacin.
Enrichment restores nutrients: Many white rice products are fortified with B vitamins to add back the niacin and other nutrients lost during milling.
Bioavailability differs between types: Niacin in whole grains like brown rice is less bioavailable, meaning the body absorbs less of it compared to the free-form niacin added to enriched grains.
Parboiling helps retain niacin: Soaking and steaming rice before milling (parboiling) helps transfer some B vitamins from the outer layers to the endosperm, preserving more niacin than standard milling.
Rice is not a primary source: While rice contributes to intake, other foods like meat, fish, and fortified cereals are richer and more readily absorbed sources of niacin.

Understanding Niacin (Vitamin B3)

Niacin, also known as vitamin B3, is a water-soluble vitamin essential for hundreds of enzyme reactions in the body. Its primary function involves converting carbohydrates, fats, and proteins into usable energy for cells. A deficiency can lead to pellagra, a severe condition with symptoms affecting the skin, digestive system, and nervous system. In the past, communities with diets centered on unenriched grains, like corn or white rice, were most at risk for this condition. Today, fortification of staple foods has made pellagra rare in many parts of the world.

Niacin in Brown Rice vs. White Rice

The presence and quantity of niacin in rice are heavily influenced by the grain's processing. To understand the difference, it helps to know the structure of a rice kernel. It consists of the outer husk, the bran layer, and the germ, which surround the starchy endosperm. Brown rice is a whole grain that retains the bran and germ, while white rice has these layers removed during milling.

The Case for Brown Rice

Because it is less processed, brown rice naturally contains more niacin than unenriched white rice. The niacin is concentrated in the bran and germ, which are kept intact in the whole grain. For example, a cup of cooked brown rice may contain about 5.2 mg of niacin. However, there is a crucial caveat: the natural niacin in whole grains is less bioavailable. This means it is bound to complex molecules, and only about 30% of it is readily absorbed by the body.

The Story of White Rice

White rice begins its life as brown rice, but the milling process strips away the bran and germ layers, along with a significant portion of its natural vitamins and minerals, including niacin. To compensate for this nutritional loss, many white rice products are enriched or fortified with B vitamins, including niacin, along with iron. This practice adds back some of the lost nutrients, providing a measurable dose of niacin. A cup of enriched white rice can contain around 2.3 mg of niacin. The niacin in fortified rice is also more bioavailable compared to the naturally occurring niacin in brown rice.

The Impact of Processing on Niacin Content

Various processing methods alter the final niacin content and absorption. Here are a few key examples:

Milling: As detailed above, milling is the primary cause for the loss of natural niacin when brown rice is processed into white rice.
Fortification: The deliberate addition of niacin to refined rice products is a public health strategy to prevent nutrient deficiencies. This process ensures a more consistent level of bioavailable niacin in the final product.
Parboiling: This technique involves soaking and steaming rice before milling. This process moves some of the water-soluble B vitamins, including niacin, from the bran into the starchy endosperm, so they are not entirely lost during milling. As a result, parboiled rice tends to retain more niacin than standard milled white rice.

Comparing Niacin in Different Rice Types


Feature	Brown Rice	Enriched White Rice
Processing	Minimally processed; bran and germ intact.	Heavily milled to remove bran and germ; fortified afterwards.
Niacin Content	Naturally higher niacin levels (e.g., 5.2 mg per cup).	Lower natural niacin, but fortified to add it back (e.g., 2.3 mg per cup).
Bioavailability	Lower absorption rate (~30%) due to bound niacin.	Higher absorption rate due to added, free niacin.
Other Nutrients	Higher fiber, magnesium, and phosphorus.	Lower natural vitamin content, but added nutrients like folic acid.

Other Dietary Sources of Niacin

While rice can contribute to your niacin intake, it is far from the richest source. A balanced diet incorporates a variety of foods to ensure adequate intake. Some of the most potent sources include:

Animal Products: Liver, chicken breast, tuna, salmon, and ground beef are excellent sources of highly bioavailable niacin.
Nuts and Seeds: Peanuts and sunflower seeds offer significant amounts of niacin.
Legumes: Lentils and green peas also provide niacin.
Fortified Cereals: Many breakfast cereals are heavily fortified with B vitamins, including niacin.
Mushrooms and Avocados: These are good plant-based sources of niacin.

Bioavailability: Why It Matters

The term bioavailability is key when discussing niacin from rice. For brown rice, even though the raw nutrient count is higher, the body cannot fully utilize all of it because it's in a bound form. In contrast, the niacin added to enriched white rice is in a free, more readily absorbable form. For individuals relying on rice as a primary source of vitamins, this distinction is important for preventing deficiency. A diverse diet including other niacin-rich foods is the most reliable way to ensure sufficient intake. For more information on niacin's health benefits, you can consult sources like Harvard's School of Public Health: Niacin – Vitamin B3 - The Nutrition Source

Conclusion: Making Informed Choices

Yes, niacin is found in rice, but it's a nuanced situation. The amount you get depends heavily on whether you choose brown rice or enriched white rice. Brown rice contains more natural niacin, but its absorption is less efficient. Enriched white rice, while stripped of its natural bran and germ, has bioavailable niacin added back during fortification. For most people with a varied diet, either option contributes to a healthy intake of B vitamins. However, for those with restrictive diets or specific health concerns, understanding the differences in processing and bioavailability is crucial for making informed dietary choices.

Frequently Asked Questions

Brown rice naturally contains more niacin because the nutrient is concentrated in the bran and germ layers, which are removed to make white rice. However, the niacin in brown rice is less bioavailable than the niacin added to enriched white rice.

Niacin is added to white rice during the enrichment process to restore the nutrients, including B vitamins and iron, that are lost when the bran and germ are removed during milling. This is a public health strategy to prevent deficiencies.

The niacin added to fortified rice is in a free form, which is more readily absorbed and utilized by the body compared to the naturally occurring, bound niacin found in whole grains like brown rice.

Pellagra is a disease caused by severe niacin deficiency. Historically, it was seen in populations whose diets relied heavily on unenriched grains like corn and milled white rice, which have very low niacin content.

Yes, cooking can affect niacin content. Like other water-soluble vitamins, some niacin can leach into the cooking water. Parboiling rice is a process that actually helps to retain niacin by moving it into the grain's endosperm before milling.

Excellent sources of niacin include animal products like meat, poultry, and fish (especially tuna), as well as peanuts, mushrooms, and fortified cereals.

For those seeking the highest overall concentration of bioavailable niacin from rice, enriched white rice can be a more effective source due to the fortification process. Brown rice provides a broader spectrum of nutrients like fiber and minerals, but its natural niacin is less readily absorbed.

Rinsing fortified white rice can remove some of the added niacin, as it is a water-soluble vitamin that is often on the surface of the grain. This is less of a concern for brown rice, but generally, it's best to avoid excessive rinsing of enriched grains.