changing equations

The very microbes that helped humans evolve now make us sick

Our bodies have not changes as much as the standard for what constitutes a good microbe versus a bad one.

Between the mid-1990s and the mid-2000s alone, the likelihood of having a classmate with a food allergy increased by 20 per cent in the United States. In fact, over the past five decades, the incidence of all allergies and autoimmune diseases – caused by your body attacking itself – has skyrocketed. What could explain our sudden hypersensitivity to our surroundings and ourselves? Since evolution operates on the timescale of millennia, the culprits lie not in our genes but somewhere within our environment.

One thing that has changed in public health is our awareness of germs and how they spread. In response to that insight, over the past half-century our implementation of hygiene practices has spared us from debilitating infections and enormous human misery. But the new vigilance might have altered the development of our immune system, the collection of organs that fight infections and internal threats to our health.

The idea that too clean an environment might be harmful has been dubbed “the hygiene hypothesis”. The concept has been perverted by some to suggest that the less clean the environment, the better. But its meaning is different: it is not dirt that we are missing but exposure to certain microbes that normally contribute to the development of our immune system. “It’s not that we aren’t exposed enough to microbes but that we’re not exposed to the right types of microbes,” says the immunobiologist Ruslan Medzhitov at the Yale School of Medicine, also head of the Food Allergy Science Initiative at the Broad Institute.

So what has changed? In short, it’s the standard for what constitutes a good microbe versus a bad one. “Take bacterial species that increase nutrient absorption from food,” Medzhitov says. These were immensely beneficial at a time where you had to go days without eating. Today in the parts of the world with an overabundance of food, having such bacteria in your intestine contributes to obesity. “Microbes that cause intestinal inflammation are another example of what we call bad microbes because they induce [detrimental immune] responses. But in the past, these microbes could have protected you from intestinal pathogens,” he adds.

The most common such foes are helminths, commonly known as intestinal worms. While they have been eradicated in most of the economic West, their absence from our environment might be contributing to the increase in allergic and autoimmune diseases by diverting our immune system’s attention towards our food and ourselves. This is what Ken Cadwell, a microbiologist at New York University, contends. He is interested in better understanding Crohn’s, an autoimmune disease caused by our immune system attacking our gastrointestinal tract.

Worm treatment

Cadwell’s team discovered that the bacterium Bacteroides vulgatus causes reduced mucus secretion in mice, something that results in the condition. In collaboration with the parasitologist P’ng Loke, also at NYU, Cadwell then decided to treat mice that had Crohn’s disease with helminths, known to trigger mucus secretions in the intestine. And it worked! The two researchers identified that the ensuing establishment of Clostridiales bacteria in the gut cured the mice.

But would it work in humans? Loke collected stool samples from populations living in helminth-endemic areas in Malaysia before and after deworming treatment, and he noticed something intriguing. People from these regions had abundant Clostridiales in their gut before treatment and a lower incidence of autoimmune bowel diseases. After successful deworming, the protective bacteria disappeared, setting the stage for autoimmune illness to rear its head.

Yet treating humans with worms will not work as a public-health measure. Worm treatment is beneficial only for those Crohn’s patients with a genetic make-up causing reduced mucus-secretion and lacking Clostridiales bacteria. For everybody else, it is just a harmful infection. Now scientists are trying to better understand how to reap the benefits of worm therapy while avoiding its downsides. “I am more in favour of an alternative that gives the same [health] effect without having to give somebody a live parasite,” says Cadwell. “That would be ideal.”

Besides the change in our exposure to microbes, our modern lives include diets much higher in sugar, salt and carbs. Now a team from Harvard and Yale has discovered that even moderate increases in salt consumption trigger activation of immune actors, known as Th17 cells, especially prevalent in such autoimmune diseases as arthritis and multiple sclerosis, to name just two. “Recent studies found that if you have the right [genes], your likelihood of developing rheumatoid arthritis goes up 10-fold from the average risk in the population. But if you combine that with smoking, it leads to an increased risk of 100-fold. Now a recent study also showed that if you have the right [genes], you smoke, but you also consume a high-salt diet, the risk goes up 500-fold,” says the immunologist Vijay Kuchroo at Harvard, who did the work with his colleague, the neurologist David Hafler of Yale.

We are forced to conclude that the explosion of allergies and autoimmune diseases results from a mismatch between genes selected by pressures of our evolutionary past and the reality of modern life. While we have adapted in the past, we might not be able to adapt again by relying on biology alone. There is no going back – the old world is gone. To curtail the increase in allergies and autoimmunity, we have to evolve our social, political and scientific regimes, providing healthier food options at lower cost and improving our understanding of the underlying immunological mechanisms at play.

The writer is a graduate student in immunology at the Iwasaki Lab at the Yale School of Medicine.

This article was first published on Aeon.

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Top picks, best deals and all that you need to know for the Amazon Great Indian Festival

We’ve done the hard work so you can get right to what you want amongst the 40,000+ offers across 4 days.

The Great Indian Festival (21st-24th September) by Amazon is back and it’s more tempting than ever. This edition will cater to everyone, with offers on a range of products from electronics, home appliances, apparel for men and women, personal care, toys, pet products, gourmet foods, gardening accessories and more. With such overwhelming choice of products and a dozen types of offers, it’s not the easiest to find the best deals in time to buy before your find gets sold out. You need a strategy to make sure you avail the best deals. Here’s your guide on how to make the most out of the Great Indian Festival:

Make use of the Amazon trio – Amazon Prime, Amazon Pay and Amazon app

Though the festival officially starts on 21st, Amazon Prime members will have early access starting at 12 noon on 20th September itself, enabling them to grab the best deals first. Sign up for an Amazon Prime account to not miss out on exclusive deals and products. Throughout the festival, Prime members will 30-minute early access to top deals before non-Prime members. At Rs 499/- a year, the Prime membership also brings unlimited Amazon Prime video streaming and quick delivery benefits.

Load your Amazon pay wallet; there’s assured 10% cashback (up to Rs 500). Amazon will also offer incremental cashbacks over and above bank cashbacks on select brands as a part of its Amazon Pay Offers. Shopping from the app would bring to you a whole world of benefits not available to non-app shoppers. App-only deals include flat Rs 1,250 off on hotels on shopping for more than Rs 500, and flat Rs 1,000 off on flights on a roundtrip booking of Rs 5,000 booking from Yatra. Ten lucky shoppers can also win one year of free travel worth Rs 1.5 lakhs.

Plan your shopping

The Great Indian Sale has a wide range of products, offers, flash sales and lightning deals. To make sure you don’t miss out on the best deals, or lose your mind, plan first. Make a list of things you really need or have been putting off buying. If you plan to buy electronics or appliances, do your research on the specs and shortlist the models or features you prefer. Even better, add them to your wishlist so you’re better able to track your preferred products.

Track the deals

There will be lightning deals and golden hour deals throughout the festival period. Keep track to avail the best of them. Golden-hour deals will be active on the Amazon app from 9.00pm-12.00am, while Prime users will have access to exclusive lightning deals. For example, Prime-only flash sales for Redmi 4 will start at 2.00pm and Redmi 4A at 6.00pm on 20th, while Nokia 6 will be available at Rs 1,000 off. There will be BOGO Offers (Buy One Get One free) and Bundle Offers (helping customers convert their TVs to Smart TVs at a fraction of the cost by using Fire TV Stick). Expect exclusive product launches from brands like Xiaomi (Mi Band 2 HRX 32 GB), HP (HP Sprocket Printer) and other launches from Samsung and Apple. The Half-Price Electronics Store (minimum 50% off) and stores offering minimum Rs 15,000 off will allow deal seekers to discover the top discounts.

Big discounts and top picks

The Great Indian Festival is especially a bonanza for those looking to buy electronics and home appliances. Consumers can enjoy a minimum of 25% off on washing machines, 20% off on refrigerators and 20% off on microwaves, besides deals on other appliances. Expect up to 40% off on TVs, along with No-Cost EMI and up to Rs 20,000 off on exchange.

Home Appliances

Our top picks for washing machines are Haier 5.8 Kg Fully Automatic Top Loading at 32% off, and Bosch Fully Automatic Front Loading 6 Kg and 7 Kg, both available at 27% discount. Morphy Richards 20 L Microwave Oven will be available at a discount of 38%.

Our favorite pick on refrigerators is the large-sized Samsung 545 L at 26% off so you can save Rs 22,710.

There are big savings to be made on UV water purifiers as well (up to 35% off), while several 5-star ACs from big brands will be available at greater than 30% discount. Our top pick is the Carrier 1.5 Ton 5-star split AC at 32% off.

Personal Electronics

There’s good news for Apple fans. The Apple MacBook Air 13.3-inch Laptop 2017 will be available at Rs 55,990, while the iPad will be available at 20% off. Laptops from Lenovo, Dell and HP will be available in the discount range of 20% to 26%. Top deals are Lenovo Tab3 and Yoga Tab at 41% to 38% off. Apple fans wishing to upgrade to the latest in wearable technology can enjoy Rs 8,000 off on the Apple Watch series 2 smartwatch.

If you’re looking for mobile phones, our top deal pick is the LG V20 at Rs 24,999, more than Rs 5000 off from its pre-sale price.

Power banks always come in handy. Check out the Lenovo 13000 mAh power bank at 30% off.

Home printers are a good investment for frequent flyers and those with kids at home. The discounted prices of home printers at the festival means you will never worry about boarding passes and ID documents again. The HP Deskjet basic printer will be available for Rs 1,579 at 40% off and multi-function (printer/ scanner/ Wi-Fi enabled) printers from HP Deskjet and Canon will also available at 33% off.

The sale is a great time to buy Amazon’s native products. Kindle E-readers and Fire TV Stick will be on sale with offers worth Rs 5,000 and Rs 1,000 respectively.

The Amazon Fire Stick
The Amazon Fire Stick

For those of you who have a bottomless collection of movies, music and photos, there is up to 60% off on hard drives and other storage devices. Our top picks are Rs 15,000 and Rs 12,000 off on Seagate Slim 5TB and 4TB hard drives respectively, available from 8.00am to 4.00pm on 21st September.

The sale will see great discounts of up to 60% off on headphones and speakers from the top brands. The 40% off on Bose QC 25 Headphones is our favourite. Top deals are on Logitech speakers with Logitech Z506 Surround Sound 5.1 multimedia Speakers at 60% off and Logitech X300 Bluetooth Speaker at 58% off!

Other noteworthy deals

Cameras (up to 55% off) and camera accessories such as tripods, flash lights etc. are available at a good discount. Home surveillance cameras too will be cheaper. These include bullet cameras, dome cameras, simulated cameras, spy cameras and trail and game cameras.

For home medical supplies and equipment, keep an eye on the grooming and personal care section. Weighing scales, blood pressure monitors, glucometers, body fat monitors etc. will be available at a cheaper price.

The sale is also a good time to invest in home and kitchen supplies. Mixer-grinders and juicers could see lightning deals. Don’t ignore essentials like floor mops with wheels, rotating mop replacements, utensils, crockery etc. Tupperware sets, for example, will be more affordable. There are attractive discounts on bags, especially laptop bags, backpacks, diaper bags and luggage carriers.

Interesting finds

While Amazon is extremely convenient for need-based shopping and daily essentials, it is also full of hidden treasures. During the festival, you can find deals on telescopes, polaroid cameras, smoothie makers, gym equipment, gaming consoles and more. So you’ll be able to allow yourself some indulgences!

Small shopping

If you have children, the festival is good time to stock up on gifts for Diwali, Christmas, return gifts etc. On offer are gaming gadgets such as Xbox, dough sets, Touching Tom Cat, Barbies, classic board games such as Life and more. There are also some products that you don’t really need, but kind of do too, such as smartphone and tablet holders, magnetic car mounts for smartphones and mobile charging station wall stands. If you’re looking for enhanced functionality in daily life, do take a look at the Amazon Basics page. On it you’ll find USB cables, kitchen shears, HDMI cables, notebooks, travel cases and other useful things you don’t realise you need.

Check-out process and payment options

Amazon is also offering an entire ecosystem to make shopping more convenient and hassle-free. For the festival duration, Amazon is offering No-Cost EMIs (zero interest EMIs) on consumer durables, appliances and smartphones, plus exchange schemes and easy installation services in 65 cities. HDFC card holders can avail additional 10% cashback on HDFC credit and debit cards. Customers will also get to “Buy Now and Pay in 2018” with HDFC Credit Cards, as the bank offers a 3 Month EMI Holiday during the days of the sale. Use Amazon Pay balance for fast and easy checkouts, quicker refunds and a secured shopping experience.

Sales are fun and with The Great Indian Festival offering big deals on big brands, it definitely calls for at least window shopping. There’s so much more than the above categories, like minimum 50% off on American Tourister luggage! To start the treasure hunt, click here.

This article was produced by the Scroll marketing team on behalf of Amazon.in and not by the Scroll editorial team.