The Science of Buckwheat Hulls

Filling your floor cushion or pillow with a natural filler like buckwheat hulls is a sustainable choice that keeps potentially toxic synthetic materials out of landfills and out of your home. Using buckwheat hulls has several other important advantages too, all of which are related to their plant-based origins.

Plant Defense

Plants have a difficult life. They don’t have the luxury of walking or running away from predators or pests like we do. But this curse is also a blessing. Because they lack mobility plants have evolved several impressive defense strategies that protect them against pests and predators. A simple example of a defense strategy is a plant that grows thorns. The thorns deter herbivores from grazing the plant before it has a chance to reproduce. Another school of defenses are the chemical defense strategies. Plants like buckwheat produce a host of chemical compounds that can protect them in many ways. Some compounds dissuade herbivores from eating them by making the plant less appealing. Other compounds cause a stinging sensation on contact. There are also compounds that can inhibit disease-causing organisms such as fungus and bacteria.

Because they come from a plant, a major advantage of buckwheat hulls as a cushion filling material is that they contain chemical compounds that inhibit the growth of bad bacteria. This inhibition is also known as antimicrobial activity. Antimicrobial activity is the ability for some agent (chemical compounds, in this case) to kill or retard the growth of microorganisms, such as bacteria and fungi. The antimicrobial activity of buckwheat hulls is due to the evolved chemical defenses of the buckwheat plant. The chemical compound classes responsible for the antimicrobial activity of buckwheat hulls are phenolic compounds and fatty-acids.

Using a filling material that has natural antimicrobial activity will ensure that your cushion is free of bacterial growth. Bacterial species, such as Staphylococcus aureus and Escherichia coli, cause odour and disease - it is important to keep your cushion and home free of them.

Chemical Defense Strategies

Phenolic compounds play several important roles in plants. They mediate the release and suppression of plant growth hormones. Specific phenolics, like flavonoids, deter herbivores by producing negative sensory stimuli. Flavonoids play a role in protecting plants against disease-causing organisms (fungus, bacteria), evidenced by the fact that many plants will synthesize flavonoids in response to microbial infections. In short, flavonoids are a mechanism for a plants’ antimicrobial activity. 

Fatty acids are compounds that contain a carboxylic acid and a long aliphatic chain. What this means is that fatty acids are an important dietary component for animals. In addition, fatty acids play an integral role in the structure of cellular membranes, including bacterial cell walls. Consider a brick wall, the strength of the wall depends on having the correct ratio of bricks to mortar. Cell membranes are similar in that they require specific ratios of their constituents to function correctly and protect the microorganism. Introducing fatty acids from an external source (E.g. buckwheat hulls) can upset the balance of a cellular membrane and lead to defects of weaknesses in the membrane. Buckwheat hulls create defects and weaknesses in bacterial cell walls and prevent bacterial cells from functioning and reproducing normally, inhibiting the growth of bad bacteria in your home. Neither a wall made entirely of bricks nor entirely of mortar are effective.

Cellular membranes act like the walls around a castle, protecting the bacterial cell from intruders, toxins, etc. In addition, the cell membrane is responsible for mediating the internal conditions of the cell that allow for regular function. By interfering with the cellular membrane the chemical compounds in buckwheat hulls stop the bacterial cells from going about their business as usual, they disrupt the bacteria’s ability to function and reproduce normally leading to the inhibition of bacteria.

Antimicrobial Activity

Scientists measured the antimicrobial activity of buckwheat hulls against several microbial species. Staphylococcus aureus, Salmonella choleraesuis, and Escherichia coli, among others. The microbial species most affected by the buckwheat hull extracts were Gram-positive species. “Gram-positive” is a classification of bacteria based on the characteristics of their cell walls. Staphylococcus aureus is an example of a Gram-positive bacteria. Gram-positive bacteria have a pronounced cell wall and are more susceptible to compounds that interfere with cellular membranes, like fatty acids and phenolics.

Researchers suspect that the flavonoids in buckwheat hulls interact with proteins and enzymes in bacterial cells. Specifically, the flavonoids inhibit important enzymes and proteins that bacterial cell walls depend on for normal function. Flavonoids and fatty acids are like two armies waging a two-front war on bacteria and other microbes; both chemical compound classes negatively affect the bacterial cells walls in different manners. By weakening and disrupting the cell walls the chemical compounds of buckwheat hulls inhibit the growth of bad bacteria.

The last thing you want is odour and disease causing bacteria like Staphylococcus aureus or Escherichia coli growing unchecked in your floor cushion or in your home. By filling your floor cushion or pillow with buckwheat hulls, you are providing a natural shield against these bad bacteria. The chemical compounds in buckwheat hulls will interfere with the cell wall of the bacterial cells. Much like a castle that has had its walls breached, bacteria in the presence of buckwheat hulls will be conquered. 

Additional Benefits

Research has shown that the flavonoids in buckwheat hulls also have significant antioxidant activity. Antioxidants are considered by many to be an important dietary constituent as they are believed to protect one’s cells from oxidation. Oxidation in the cells of the human body lead to the creation of free radicals or reactive oxygen species, imbalances in the concentration of reactive oxygen species can lead to oxidative stress that causes damage to all the components of a cell. 

Studies have also shown that the flavonoids present in buckwheat hulls act as a microcirculation enhancer. Microcirculation is the circulation of blood in the body’s smallest blood vessels. Promoting microcirculation supports the delivery of nutrients and oxygen throughout the body and can aid the body’s response to inflammation. Inflammation has been associated with several negative health outcomes. Body pain, insomnia, fatigue, gastrointestinal issues, and a weakened immune system. 

Buckwheat hulls are a sustainable filling material that will keep your home and the landfill free of potentially toxic synthetic fillers. Additionally, the chemical defense strategies of buckwheat hulls can be repurposed to keep your floor cushion and home free of odour and disease causing bacteria, like Staphylococcus aureus or Escherichia coli. The antimicrobial activity of buckwheat hulls is due to the presence of flavonoid and fatty acid chemical compounds in the hulls. These compounds disturb the cell walls of bacteria and stop the bacteria from functioning normally or reproducing, halting its growth. Filling your floor cushion with buckwheat hulls will help you keep your home and everyone in it healthy and happy.

Read why we chose to fill Solum cushions with buckwheat hulls, here. If you're interested in seeing our floor cushion options, click here.


  1. Čabarkapa I. et al. Antimicrobial Activity of Buckwheat (Fagopyrum esculentums Moench) hulls extract, Food Processing, Quality and Safety. 2008, 4, 159-163.
  2. Rui Jing et al. Phytochemical and Pharmacological Profiles of Three Fagopyrum Buckwheats. Int. J. Mol. Sci. 2016, 17, 589.

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