February 2019 Issue
Sprouted Grains: Modern Trend, Ancient Method
By Carrie Dennett, MPH, RDN, CD
Vol. 21, No. 2, P. 16
Here's an overview of sprouted grains, their advantages, and what the science says.
Once upon a time, sprouted grain bread was relegated to the freezer case of "health food" stores. Today, sprouted grain products have a place on mainstream grocery store shelves as consumers increasingly seek health-promoting foods and ingredients processed using natural methods.1 Between 2006 and 2011, the average increase in sprouted grain product launches was 14%; between 2012 and 2016, that average increase rose to 26%.2
Carlee Kelly, MSN, cofounder of the Portland, Oregon-based product innovation firm Lettuce Eat Real, says the growth in sprouted grains has had a snowball effect. "Sprouted ingredients have slowly caught the attention of consumers and manufacturers alike, and it appears we have finally hit that tipping point in awareness," she says. "As sprouted ingredients have become more available, more brands are using them in their products and retailers are more familiar with seeing products with sprouted ingredients and therefore more likely to give shelf placement for these products."
Historically, sprouting was a casual affair. Farmers harvested grains, tied them into sheaves, and left them in the ﬁeld until they were ready to thresh the grain. Exposed to the weather, at least some of the grain would begin to sprout.3 But in the modern food supply, grains have been divided into two categories: viable or not viable. Viable—sproutable—grains were planted as seeds, but sprouting was deemed a defect in grains destined for the food supply, so these grains were treated with heat to kill any viability and bring the grains to a uniform moisture content.4
Now, the resurgence of sprouting has created a third category of seeds: viable seeds destined to be eaten in sprouted form. But are all sprouted grains created equal? In 2015, the Oldways Whole Grain Council (part of the Boston-based Oldways food and nutrition nonprofit) created a Sprouted Grains Working Group, collaborating with 28 companies to explore the standards and definitions for sprouted grains and learn about common production approaches.5
What Sprouting Means
"A sprouted grain is a germinated seed," Kelly says. "Germination is awakening the seed from its dormant state." Sprouting means that a viable, intact grain has been germinated intentionally through a controlled process using moisture, temperature, and time. Conversely, if grains have accidentally "field-sprouted," they may not be safe for human consumption.5
"Not all grains sprout," says Kelly Toups, MLA, RD, LDN, director of nutrition at Oldways. "This could be because they're older or dried out … [or] they've been treated to reduce sprouting." So-called "dead" seeds are less expensive to purchase, so companies could enter the sprouted grain market unfairly by purchasing nonviable seed, soaking it, drying it, and then calling it sprouted. In addition, some grain varieties have been bred to resist sprouting in the field, so they're not well suited for intentional sprouting.5
There are several ways to test for viability. Grains can be test sprouted to assess whether all, or most, of the batch is capable of sprouting. While germination rates vary from grain to grain, 85% to 90% may be a good range. Companies also can use biochemical testing, such as the tetrazolium test; tetrazolium salt stains all living tissue in the grain embryo red, allowing for a quick estimate of germination potential.5
Sprouted grains straddle the line between seed and new plant. During germination, grains undergo biochemical reactions that alter their nutritional composition. This includes a structural breakdown of macronutrients, increased availability of micronutrients, and reduction in antinutrients.
"Larger proteins are broken down into their amino acid components," Kelly says. "The essential amino acids actually increase. It's not only about protein content and quantity but [also] protein quality and availability."6-8 Sprouting also degrades some of the gliadin peptides in gluten-containing grains, which may make them digestible to some individuals with nonceliac gluten sensitivity.9 Depending on length of the sprouting process, the percentage of fiber content may increase as starch decreases.6
Sprouting increases the bioavailability of iron, zinc, calcium, magnesium, manganese, potassium, phosphorus, and folic acid.6,9,10 Levels of the antioxidant vitamins and phytochemicals, including phenolic compounds and flavonoids, also increase, sometimes multifold.7,8,11-14
Sprouting also reduces levels of antinutrients, notably phytic acid.15,16 Phytic acid is a storage form of phosphorus that binds the micronutrients the grain needs to fuel germination and propagation, were the grain to be planted as a seed, forming phytates. In this bound state, those nutrients can't be absorbed by the digestive tract, because humans and animals lack sufficient quantities of the enzyme phytase in the small intestine.17,18 Sprouting increases phytase levels in the grain. "Once phytase breaks the phytate apart, these bound nutrients become available for us to digest," Kelly says. It should be noted that phytates have antioxidant and anti-inflammatory properties, and research suggests that they may help prevent CVD, type 2 diabetes, and some forms of cancer, including colon, breast, and prostate cancers.17,18
The Oldways working group report says that ideally, nutritional changes should be measured to stop sprouting at peak nutritional transformation. However, this is hard to measure, and not all nutritional changes peak at the same time from grain to grain, or even within a single grain.5 Therefore, simply documenting that sprouting has occurred is the current best practice.
Toups says that looking for visible sprouting is one method, but not always the best method. "A grain could be sprouted even if you don't see the sprout. The sprout may have fallen off in the drying process, or the grains in a batch may sprout at different rates under the same conditions," she says.
Some seeds, such as amaranth, may be so small that the sprout isn't visible to the naked eye. The USDA allows sprouted grains to be considered whole grains—still seeds, not yet vegetables or other plants—provided that the sprout growth doesn't exceed kernel length and nutrient values haven't diminished.19
Other ways to document sprouting include measuring increases in alpha-amylase, the enzyme that catalyzes the conversion of starch into sugars; phytase; or free amino acids. Toups says that while sprouted grains tend to have higher levels of alpha-amylase and phytase, the amounts are somewhat grain dependent, so there aren't universal benchmarks.5 Increases in amino acids can be documented by measuring the rise in gamma-aminobutyric acid, or GABA, which can increase significantly with sprouting.20
Nutrition aside, sprouted grains can offer flavor and texture options. Kelly says they have a nutty, earthy flavor profile, and that, once sprouted and properly handled and organically sanitized in a commercial facility, some grains become ready to eat, making them useful as crunchy toppings for yogurt and salads, or in granola and cereals. Faster prep time is another selling point in foodservice and among consumers. "The longer that a grain is sprouted, the less time it is going to require for cooking," Kelly says.
Many industrial bread bakers add vital wheat gluten to breads to help them rise, but research done at Ardent Mills, a grain and flour supplier based in Denver, found that flour from wheat sprouted in a controlled environment produced bread dough with a 5% to 9% increase in volume, allowing vital wheat gluten to be reduced or even eliminated.21 This may seem surprising, since gluten (gliadin) is one protein that can break down during sprouting, but one day of sprouting wasn't enough time to break down the gluten-forming proteins, contributing to a stable gluten network.
Toups says sprouting grains at home is easy, but food safety is important. "To sprout grains at home, you basically just have to take whole grains that have been rinsed and drained, then soak them in water overnight, and drain them in a vented jar," she says. "Because moist environments pose the risk of bacterial growth, we highly recommend cooking your sprouted grains before eating them."
While sprouted grains can offer many unique nutrition and culinary advantages and may be particularly beneficial for patients with gluten sensitivity or blood sugar management issues, some bloggers tell their readers that the only grains they should eat are sprouted grains. However, Toups says shunning nonsprouted grains is a mistake.
"While some sprouted grains may have slightly higher levels of certain nutrients than their regular whole grain counterparts, this is not necessarily the case in every single situation," she says. "Sprouted or not, all whole grains contain more fiber, protein, and higher levels of many essential nutrients than their refined counterparts. As health professionals, our first priority should be getting more people to make more of their grains whole, regardless of whether or not they are sprouted."
Kelly says the truth is somewhere in the middle. "I think it is important for us not to get too absolute on a topic like this—the scientific exploration of this very traditional food preparation method is still in its infancy. There is a lot we still don't know for certain."
— Carrie Dennett, MPH, RDN, CD, is the nutrition columnist for The Seattle Times, owner of Nutrition By Carrie, and author of Healthy for Your Life: A Holistic Guide to Optimal Wellness.
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