Are you one of these people who loathes spending time outdoors at dusk as the weather warms and mosquitoes start biting?

Female mosquitoes need blood to develop their eggs. Even though they take a tiny amount of our blood, they can leave us with itchy red lumps that can last days. And sometimes something worse.

So why does our body react and itch after being bitten by a mosquito? And why are some people more affected than others?

What happens when a mosquito bites?

Mosquitoes are attracted to warm blooded animals, including us. They’re attracted to the carbon dioxide we exhale, our body temperatures and, most importantly, the smell of our skin.

The chemical cocktail of odours from bacteria and sweat on our skin sends out a signal to hungry mosquitoes.

Some people’s skin smells more appealing to mosquitoes, and they’re more likely to be bitten than others.

Once the mosquito has made its way to your skin, things get a little gross.

The mosquito pierces your skin with their “proboscis”, their feeding mouth part. But the proboscis isn’t a single, straight, needle-like tube. There are multiple tubes, some designed for sucking and some for spitting.

Once their mouth parts have been inserted into your skin, the mosquito will inject some saliva. This contains a mix of chemicals that gets the blood flowing better.

There has even been a suggestion that future medicines could be inspired by the anti-blood clotting properties of mosquito saliva.

It’s not the stabbing of our skin by the mosquito’s mouth parts that hurts, it’s the mozzie spit our bodies don’t like.

Are some people allergic to mosquito spit?

Once a mosquito has injected their saliva into our skin, a variety of reactions can follow. For the lucky few, nothing much happens at all.

For most people, and irrespective of the type of mosquito biting, there is some kind of reaction. Typically there is redness and swelling of the skin that appears within a few hours, but often more quickly, after just a few minutes.

Occasionally, the reaction can cause pain or discomfort. Then comes the itchiness.

Some people do suffer severe reactions to mosquito bites. It’s a condition often referred to as “skeeter syndrome” and is an allergic reaction caused by the protein in the mosquito’s saliva. This can cause large areas of swelling, blistering and fever.

The chemistry of mosquito spit hasn’t really been well studied. But it has been shown that, for those who do suffer allergic reactions to their bites, the reactions may differ depending on the type of mosquito biting.

We all probably get more tolerant of mosquito bites as we get older. Young children are certainly more likely to suffer more following mosquito bites. But as we get older, the reactions are less severe and may pass quickly without too much notice.

How best to treat the bites?

Research into treating bites has yet to provide a single easy solution.

There are many myths and home remedies about what works. But there is little scientific evidence supporting their use.

The best way to treat mosquito bites is by applying a cold pack to reduce swelling and to keep the skin clean to avoid any secondary infections. Antiseptic creams and lotions may also help.

There is some evidence that heat may alleviate some of the discomfort.

It’s particularly tough to keep young children from scratching at the bite and breaking the skin. This can form a nasty scab that may end up being worse than the bite itself.

Applying an anti-itch cream may help. If the reactions are severe, antihistamine medications may be required.

To save the scratching, stop the bites

Of course, it’s better not to be bitten by mosquitoes in the first place. Topical insect repellents are a safe, effective and affordable way to reduce mosquito bites.

Covering up with loose fitted long sleeved shirts, long pants and covered shoes also provides a physical barrier.

Mosquito coils and other devices can also assist, but should not be entirely relied on to stop bites.

There’s another important reason to avoid mosquito bites: millions of people around the world suffer from mosquito-borne diseases. More than half a million people die from malaria each year.

In Australia, Ross River virus infects more than 5,000 people every year. And in recent years, there have been cases of serious illnesses caused by Japanese encephalitis and Murray Valley encephalitis viruses.

Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

You’ve probably seen recent claims online seed oils are “toxic” and cause inflammation, cancer, diabetes and heart disease. But what does the research say?

Overall, if you’re worried about inflammation, cancer, diabetes and heart disease there are probably more important things to worry about than seed oils.

They may or may not play a role in inflammation (the research picture is mixed). What we do know, however, is that a high-quality diet rich in unprocessed whole foods (fruits, vegetables, nuts, seeds, grains and lean meats) is the number one thing you can to do reduce inflammation and your risk of developing diseases.

Rather than focusing on seed oils specifically, reduce your intake of processed foods more broadly and focus on eating fresh foods. So don’t stress out too much about using a bit of seed oils in your cooking if you are generally focused on all the right things.

What are seed oils?

Seed oils are made from whole seeds, such as sunflower seeds, flax seeds, chia seeds and sesame seeds. These seeds are processed to extract oil.

The most common seed oils found at grocery stores include sesame oil, canola oil, sunflower oil, flaxseed oil, corn oil, grapeseed oil and soybean oil.

Seed oils are generally affordable, easy to find and suitable for many dishes and cuisines as they often have a high smoke point.

However, most people consume seed oils in larger amounts through processed foods such as biscuits, cakes, chips, muesli bars, muffins, dipping sauces, deep-fried foods, salad dressings and margarines.

These processed foods are “discretionary”, meaning they’re OK to have occasionally. But they are not considered necessary for a healthy diet, nor recommended in our national dietary guidelines, the Australian Guide for Healthy Eating.

I’ve heard people say seed oils ‘promote inflammation’. Is that true?

There are two essential types of omega fatty acids: omega-3 and omega-6. These are crucial for bodily functions, and we must get them through our diet since our bodies cannot produce them.

While all oils contain varying levels of fatty acids, some argue an excessive intake of a specific omega-6 fatty acid in seed oils called “linoleic acid” may contribute to inflammation in the body.

There is some evidence linoleic acid can be converted to arachidonic acid in the body and this may play a role in inflammation. However, other research doesn’t support the idea reducing dietary linoleic acid affects the amount of arachidonic acid in your body. The research picture is not clear cut.

But if you’re keen to reduce inflammation, the best thing you can do is aim for a healthy diet that is:

• high in antioxidants (found in fruits and vegetables)
• high in “healthy”, unsaturated fatty acids (found in fatty fish, some nuts and olive oil, for example)

• high in fibre (found in carrots, cauliflower, broccoli and leafy greens) and prebiotics (found in onions, leeks, asparagus, garlic and legumes)

• low in processed foods.

If reducing inflammation is your goal, it’s probably more meaningful to focus on these basics than on occasional use of seed oils.

What about seed oils and heart disease, cancer or diabetes risk?

Some popular arguments against seed oils come from data from single studies on this topic. Often these are observational studies where researchers do not make changes to people’s diet or lifestyle.

To get a clearer picture, we should look at meta-analyses, where scientists combine all the data available on a topic. This helps us get a better overall view of what’s going on.

A 2022 meta-analysis of randomised controlled trials investigated the relationship between supplementation with omega-6 fatty acid (often found in seed oils) and cardiovascular disease risk (meaning disease relating to the heart and blood vessels).

The researchers found omega-6 intake did not affect the risk for cardiovascular disease or death but that further research is needed for firm conclusions. Similar findings were observed in a 2019 review on this topic.

The World Health Organization published a review and meta-analysis in 2022 of observational studies (considered lower quality evidence compared to randomised controlled trials) on this topic.

They looked at omega-6 intake and risk of death, cardiovascular disease, breast cancer, mental health conditions and type 2 diabetes. The findings show both advantages and disadvantages of consuming omega-6.

The findings reported that, overall, higher intakes of omega-6 were associated with a 9% reduced risk of dying (data from nine studies) but a 31% increased risk of postmenopausal breast cancer (data from six studies).

One of the key findings from this review was about the ratio of omega-3 fatty acids to omega-6 fatty acids. A higher omega 6:3 ratio was associated with a greater risk of cognitive decline and ulcerative colitis (an inflammatory bowel condition).

A higher omega 3:6 ratio was linked to a 26% reduced risk of depression. These mixed outcomes may be a cause of confusion among health-conscious consumers about the health impact of seed oils.

Overall, the evidence suggests that a high intake of omega-6 fatty acids from seed oils is unlikely to increase your risk of death and disease.

However, more high-quality intervention research is needed.

The importance of increasing your omega-3 fatty acids

On top of the mixed outcomes, there is clear evidence increasing the intake of omega-3 fatty acids (often found in foods such as fatty fish and walnuts) is beneficial for health.

While some seed oils contain small amounts of omega-3s, they are not typically considered rich sources.

Flaxseed oil is an exception and is one of the few seed oils that is notably high in alpha-linolenic acid (sometimes shortened to ALA), an omega-3 fatty acid.

If you are looking to increase your omega-3 intake, it’s better to focus on other sources such as fatty fish (salmon, mackerel, sardines), chia seeds, hemp seeds, walnuts, and algae-based supplements. These foods are known for their higher omega-3 content compared to seed oils.

The bottom line

At the end of the day, it’s probably OK to include small quantities of seed oils in your diet, as long as you are mostly focused on eating fresh, unprocessed foods.

The best way to reduce your risk of inflammation, heart disease, cancer or diabetes is not to focus so much on seed oils but rather on doing your best to follow the Australian Guide for Healthy Eating.

Lauren Ball, Professor of Community Health and Wellbeing, The University of Queensland and Emily Burch, Lecturer, Southern Cross University

This article is republished from The Conversation under a Creative Commons license. Read the original article.