Celery juice may look like water from an algae-filled pond, but its disciples have been downing it by the glassful. One of its American devotees is Jennifer Aniston, who regards the murky green potion as a treat on her cheat days, when she lets herself off the full rigours of her health-and-fitness routine. As of this morning, #celeryjuice has more than 191,000 tags on Instagram. So why is it having a moment?

What is celery juice said to do?

Stories posted to Instagram and elsewhere are anecdotal but say that the juice is the biggest medical remedy for digestive issues, autoimmune disorders, psoriasis, acne, chronic-fatigue syndrome, acid reflux, the shingles virus, strep bacteria and weight loss. Many of the stories credit Anthony William, a self-professed originator of the celery-juice craze.

Does it work?

“There’s no scientific evidence to support any of the claims being made,” says Rachel Scherr, a research scientist in nutrition at the University of California. There aren’t large studies in humans on the topic, and the little research that exists on the vegetable has been cellular or animal.

Nutritionists say other factors could be influencing juicers’ sense of wellbeing: better hydration from celery’s water content (celery juice is 94 per cent water); or a placebo effect.

Should you still drink it if there is no evidence?

“Overall, it’s a healthy juice,” says Dr Elizabeth Bradley, medical director of Cleveland Clinic’s centre for functional medicine. Celery juice has more potassium and vitamin K than tomato juice and carrot juice, but it is lower in important nutrients such as vitamin A, which is abundant in carrot juice. Unlike other vegetables that may lose polyphenols and antioxidants from the pulp or skin when juiced, Bradley says, it is unclear how much loss occurs when juicing whole celery stalks. Nevertheless, nutritionists recommend consuming a variety of vegetables and their juices, because they all have their own combination of phytochemicals, antioxidants, vitamins and minerals.

The salty flavour in 250ml of celery juice comes from the 220mg or so of sodium, an essential electrolyte that helps our bodies maintain a balance of fluids. The recommended dietary allowance is less than 2,300mg a day; exceeding that can increase blood pressure, a risk factor for heart disease and stroke.

Any reputable scientist would say there’s nothing here. Next year some other juice or food or magical mushroom will come out and offer these same properties

Juicing retains the taste and concentrates the nutrients, but many preparations reduce the fibre, which nutritionists say is the best part. The juice contains about 4g per 250ml, still far below the 25mg to 30mg recommended daily, primarily from food. Fibre helps people feel full and maintain regularity.

Like kale and spinach, celery contains antioxidants and may have anti-inflammatory properties. Compared to the stalks, the leaves are more than 20 times higher in flavones, a class of flavonoids and compounds found in plants with antioxidant properties, according to a 2017 review in the medical journal Advances in Nutrition. Food is complex, and just because a food is high in flavones doesn’t translate into guaranteed health benefits. Compounds such as flavones are modified after they are absorbed, and these modified forms might not have the same effect as what is demonstrated in preclinical studies, according to the review.

For those who were consuming few vegetables and are now drinking celery juice, nutritionists say that’s a good change.

Why is celery juice suddenly everywhere?

Many credit William, who wrote a book called Celery Juice: The Most Powerful Medicine of Our Time Healing Millions Worldwide. He shares advice with his large fan base through his podcast, his website and his bestselling books and in his contributions to Gwyneth Paltrow’s Goop website.

William, who also uses the moniker “Medical Medium”, is neither a medical doctor nor formally trained in nutrition, and his process is unconventional. “Spirit starts to speak to me, and I write every word exactly the way spirit wants it until I have a stack of notepads many feet high,” he says, adding, “It’s a gift that was given to me.”

Nutritionists call his assertions unfounded. “Any reputable scientist would say there’s nothing here,” says David Levitsky, a professor of nutrition and psychology at Cornell University. “And I guarantee you next year there will be some other juice or food or magical mushroom that will come out and offer these same properties.”

How was celery used before?

Celery – or Apium graveolens – is a relative of carrots, parsley and coriander. Before being cast into the salad drawer it had quite the illustrious history. Charles Davis, a plant evolutionary biologist at Harvard University, says that the Egyptians placed wild celery in King Tutankhamen’s tomb in 1325 BC and that the first cultivated medicinal use of celery dates to the Romans in 400 BC.

Greeks drank a wine made from it, and winning athletes wore crowns of the foliage in Panhellenic games. The seeds and fruit have long been used medicinally. “I find it intriguing that the purported medical usage of the plant is being revived today but is instead extracted from the vegetative parts,” Davis says.

Will celery juice hurt you?

“There’s nothing in it that’s going to hurt you,” Levitsky says. Celery can have a slight diuretic effect, which may increase urination and reduce some bloat. Nutritionists say patients should not stop seeing their doctor or treatment in favour of a celery-juice regimen. But something larger is at stake, Levitsky says. Believing in miraculous remedies can leave patients vulnerable to just about anything, even harmful treatments. “It thwarts belief in science and medicine to some magical mystery cure, and there ain’t no such thing.”

Is celery juice a scam?

“It’s definitely not a ‘miracle juice’,” says Rebecca Scritchfield, dietitian and author of Body Kindness. “It can join the list of the snake-oil remedies.” William, for his part, contends that he is not misleading anyone; he neither owns a celery farm nor sells the juice himself. “I’m not saying it’s a cure-all,” he says. Nutritionists say to drink celery juice if it is enjoyable, but don’t put your faith in all the claims. – New York Times