What is the best duvet inner to buy as we try to stay cosy and warm in winter, but also minimise our exposure to dust mites? 

This blog is one of two that discusses what factors there are to consider when recommending a duvet/quilt for people with  house dust mite  (HDM) allergies.

This blog discusses some of the scientific research that has been done in this area,  and what factors to look for, whereas blog 2 goes onto to discuss some different fabric options. 

Table of Contents - Blog 1 

1. Scientific research
2. Research topics and outcomes 
3. The role of barrier covers. 

Read about what factors to look for here in Blog 1, then directly compare popular duvet inner fabrics in Blog 2 .

1. Scientific Research 

Over the years there has been a range of research on what fabrics or components are best to use for bedding when people suffer from allergies, especially house dust mite (HDM) allergy. 

a) Research limitations:

• There are limitations in research - some research is sponsored by the fabric producers, so there can be bias, and the type, quality and results of research can be varied.  
• Acceptance or recommendation of fabrics can also be influenced by the amount of money an industry can devote to testing, marketing and advertising – not only to the general public but also to medical personnel.     
• Cultural factors can influence recommended outcomes, for example, it is now more common to include considerations of ecological sustainability than it was 20 or 30 years ago. 

b) Research benefits:

• Most research has focused on whether some fabrics are better for use in bedding such as quilts and duvets than others, and whether barrier covers can help protect sleepers from exposure to dust mite allergen.  This information is still valid. 
• Views have changed as the properties of modern fabrics and treatments are researched more thoroughly, and previous research discarded or challenged. These findings can help us to choose bedding that helps us to better manage our well-being.  

2. Research Topics & Outcomes 

Most research on HDM and bedding has focused on whether it is important to consider:

• HDM when purchasing bedding items such as duvets
• The age of the bedding. 
• Whether the fabric house dust mites naturally.
• Moisture wicking and breathability properties.
• If the duvet can be washed. 
• Natural fabrics - certifications and sustainability.

 These factors are discussed below. 

a) Should you consider House Dust Mites (HDM) when buying a duvet? 

Dust-mites are natural creatures – they are tiny 8-legged arthropods that live in house dust. There can be thousands of mites in a single gram of house dust (1).  They feed on organic materials, including skin scales, fungi, and bacteria, which can be found in many home soft furnishings. including beds. They are the major source of allergens in house dust.  

Dust mites as a contributor to allergies, asthma, rhinitis and atopic dermatitis / eczema.   Dust mites produce and excrete numerous allergens into the environment and their faeces (poo) can break down to fine dust.  The faeces get into the air easily and can provoke a strong allergic response when inhaled (2).  They have been linked to high levels of allergenic and asthmatic responses.  

Research recommends dust mite allergen avoidance to decrease the risk of developing a greater allergenic response. For patients with asthma, avoidance has been recommended even if they do not “test” as mite allergic, because mites also have inflammatory properties that do not show up on an allergy test (3).    

So the answer is Yes - if you are sensitized or allergic, or struggle with "hay-fever" type symptoms overnight or after sleeping, definitely consider:

• whether the duvet is one that is either less likely to harbour mites,
• or whether it can be managed in a way that can minimize the HDM population. 

 

b) Is the bedding old? 

Older bedding items are likely to have greater HDM populations than newer items, so if your duvet is old and you do not want to encase it in a barrier fabric, consider buying a new one or washing it (1). 

c) Does the duvet fibre house dust mites naturally? 

• It was thought duvets made from natural materials such as wool and feathers, were more likely to hold pools of dust mites than newly developed synthetic fabrics. Research was published where wool bedding was one cause of higher levels of dust mites in Australian homes (4) & where duvets made from feather and down waste had triggered asthma in some users (5). 
• Other studies have since indicated that synthetic bedding can be associated with more wheeze in users. On NZ study(6) showed synthetic duvets contained significantly higher levels of Der p 1 (allergen) than feather duvets, and that the advice for people with HDM sensitivity to choose synthetic bedding in preference to feather bedding wasn’t necessarily right .   
• Industry research of many natural fabrics such as wool, alpaca and silk, show them to have good moisture wicking properties, which creates an environment that discourages the growth of bacteria, fungi and dust mites. 

The varied research means synthetic microfibre is no longer considered the duvet fabric of choice simply because it can be washed. It can harbour higher levels of HDM than some other fabrics, so it should be considered alongside other natural materials such silk, alpaca, wool, feather or Tencel.  Advice for HDM sensitized people is to use barrier covers on all bedding items(1).

 

d) Moisture Management and Breathability 

Sleep research also shows that moisture management and breathability can be major bedding factors in gaining good sleep quality, and can help deter HDM populations.

• Breathability and moisture management:  Humans can lose up to one litre of water in perspiration every night as we sleep. If moisture is not managed, it will seep into your mattress or duvet/ quilt making it a better breeding ground for dust mites.
• Moisture wicking properties take moisture away from the sleeper and allow it to evaporate and promote an environment that is more resistant to dust mites.  
• Breathable fabrics help allergy sufferers to better regulate their body temperature when sleeping.   These factors contribute to better sleep and better sleep facilitates better health. 

e) Can the duvet be washed?

Research shows that whilst you need to wash in hot water (over 55℃) to kill dust-mites, washing a duvet at low temperatures will still get rid of fecal dust and allergens, making it a low cost, powerful feature when choosing a duvet/quilt.  

Natural fibres like silk, alpaca, wool and down were hard to wash, but synthetic micro-fibres were easy to clean, so for many years they were promoted as a great duvet inner choice for those with HDM allergies.  Changing research and changes in manufacturing have meant that a greater choice is now available for consumers. 

Changes in fibre technology and fabric washing:

• Washing machine and dryer technology has advanced, allowing a wider range of temperatures and settings for different fabrics and items, including duvets.
• Some wool and down duvets can now also be washed.
• The down now used to fill many feather pillows and duvets is washed and dried at over 100° C, which denatures Der p 1 and kills any uv sensitive HDM.  Quality down/feather products can be certified as hypoallergenic.
• Combinations of synthetic processes with natural products have created fibres such as Tencel, (made from wood pulp) which are used in bedding and can also be washed in low temperatures.  
• Airing quilts in the sun light will help kill dust mites as HDM are sensitive to dry conditions and ultra-violet light.  Airing can be used alongside washing.
• Dry cleaning can also be used to kill HDM as dry-cleaning uses chemicals and hot temperatures that kill mites and eggs.  There may still be dust left in the duvet, and dry cleaning does use chemicals which  people can be sensitive too. Some NZ Down companies advise dry cleaning down once a year (7)– but dust mite populations can begin to establish after 6 weeks, so HDM sensitive people may need to consider a more frequent service.  

Whatever duvet is selected, it should be cleaned and aired on a regular basis or covered with an effective dust-mite barrier encasement.  

 

f) Natural Fabrics – Certifications and sustainability

With research, testing & modern manufacturing processes, natural fabrics such as wool, alpaca, down, silk, and Tencel type fibres (eucalyptus/bamboo-based fibre), can provide hypoallergenic, breathable and sustainable bedding solutions.  

• There are also certifications now within each industry to provide consumers proof of quality, fineness and source of the fabric being used.  For example, RDS standards for Down and micron wool standards.  
• Sustainability: Most natural fabrics have the added advantage of being more sustainably sourced and they are biodegradable at their end of life, unlike microfibers or synthetics that are derived from petrochemicals/plastics. 

3) The role of a Dust Mite Barrier Duvet Cover 

Even when you have a hypoallergenic fabric – if skin cells pool in cracks and gaps or between fabric pores, then over time dust-mites and allergen builds up.  HDM levels found in international studies of duvet inners were still high.  

Regardless of duvet fabric, airing duvets in the UV sunlight and washing duvets once a season, can help to remove dust-mites, their faeces and allergen particles. The ability to hot-wash duvets to kill dust mites is rare.    Advice for HDM sensitized people is to use barrier covers on all bedding items (1,8).

Using a, MiteGuard duvet cover gives you a greater choice of duvet inner and that makes care of the inner easier.  Rather than having to wash the duvet, the MiteGuard barrier cover gets washed instead.     The inner can be aired in the sun, vacuumed and shaken outside to reduce dust and mites each season.  

Considerations when using a duvet barrier cover 

• Barrier covers add a layer of weight to the duvet, so a light washable duvet may be a better choice in Summer, depending on whether you are a hot sleeper or not. 
• Barrier coves, whilst breathable, are still tightly woven, so can reduce the overall breathability of a loosely woven microweave or fabric. 

4) Summary 

Now you know to check if your duvet inner/quilt is old, and whether it can be cleaned effectively.   When looking to buy a new one check for:

• Whether you need to consider a possible allergy to House Dust Mites
• Washability - or a means to clean it regularly
• Breathability
• Moisture wicking 
• Certifications 

To read about some of the properties of different duvet inner materials such as alpaca, wool, down and microfiber read our second blog "The Best Duvets for Dust Mite Allergy - THE FABRICS" 

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[1] Environmental assessment and exposure control of dust mites: a practice parameter-Portnoy, Williams Chew  et al Published: Ann Allergy Asthma Immunol. 2013 Dec; 111(6): 465–507.

[2] House Dust Mites -Fact Sheet prepared by the Asthma and Respiratory Foundation NZ-2010

[3] Hewitt CR, Brown AP, Hart BJ, Pritchard DI. A major house dust mite allergen disrupts the immunoglobulin E network by selectively cleaving CD23: innate protection by antiproteases. J Exp Med. 1995 Nov 1;182(5):1537-44. doi: 10.1084/jem.182.5.1537. PMID: 7595223; PMCID: PMC2192194.

[4] Garrett MH, Hooper BM, Hooper MA. Indoor environmental factors associated with house-dust-mite allergen (Der p 1) levels in south-eastern Australian houses. Allergy. 1998 Nov;53(11):1060-5. doi: 10.1111/j.1398-9995.1998.tb03815.x. PMID: 9860238.

[5] Silk waste--a further allergen in the bedroom – Sashina, Elena S., and Olga I. Yakovleva. 2023. "The Current State and Prospects of Recycling Silk Industry Waste into Nonwoven Materials" Fibers 11, no. 6: 56

[6] House dust mite allergen levels in individual bedding components in New Zealand Author: Mills, Sarah; Siebers, Robert; Wickens, Kristin; Crane, Julian; Purdie, Gordon; Fitzharris, Penny

 [7] Fairydown bedware.co.nz -guide to feather and down bedding care

[8] Preventive effect of bedding encasement with microfine fibers on mite sensitization - K Nishioka, H Yasuedo, H Saito