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A condition, known commonly as "black urine disease" or Alkaptonuria is a rare genetic disorder involving protein metabolism, and it has its root in the mutation of the homogentisate 1,2-dioxygenase gene, which in turn causes homogentisic acid accumulation in the body. The appearance of dark urine after exposure to air is due to this kind of accumulation; however, a variety of symptoms can be expected, such as joint stiffness, changes in pigmentation, and other long-term health complications. Although the prevalence has been estimated to be between 1 in 250,000 and 1 in 1 million people in the United States, its effects are indeed high on those affected.
Alkaptonuria is an autosomal recessive disease, meaning that the child must inherit a defective copy of the HGD gene from both parents. If both parents are carriers, their offspring have a 25% chance of inheriting two faulty genes and developing alkaptonuria. The condition is genetic but is often not diagnosed for years because it progresses slowly and its early symptoms appear to be harmless.
The most characteristic and common initial symptom of alkaptonuria is dark urine. The reason for this is due to the fact that excess HGA is excreted in the urine and upon oxidation in the presence of air, it gives the urine a brown or black color. Though it is often considered cosmetic, the long-term accumulation of HGA within the connective tissues produces more complicated health problems.
Progressive joint pain and stiffness: The accumulation of HGA in cartilage leads to early-onset osteoarthritis, making movement increasingly difficult over time.
Skin and eye pigmentation changes: Affected individuals may develop bluish or grayish discoloration of the sclera (white part of the eye) and the skin, particularly in areas exposed to friction.
Cardiovascular and respiratory problems: With age, HGA accumulation can lead to valve calcifications in the heart and stiffening of connective tissues in the respiratory tract, which can cause problems in middle and old age.
Decreased mobility and spinal problems: The spine may become stiff and painful due to chronic cartilage degeneration.
These symptoms usually begin to manifest during adulthood, leading to severe complications in a person's 40s or 50s and significantly affecting the quality of their life.
Because of its rarity, alkaptonuria is often mistaken or overlooked early in life. However, there are several ways to confirm the condition:
Urine Testing: The gold standard in the diagnosis is the testing of urine samples for high levels of homogentisic acid via gas chromatography. In case of oxidation, which changes the color of urine to black, it is indicative of alkaptonuria.
Genetic Testing: Confirmatory genetic testing reveals mutations of the HGD gene to diagnose the condition conclusively.
Blood Tests: High levels of HGA in the blood can be used as further evidence.
Imaging Studies: X-rays and MRIs will expose cartilage and joint damage characteristic of alkaptonuria.
At present, there is no cure for alkaptonuria; however, various treatment approaches can reduce its symptoms and slow the disease's progress:
Nitisinone Therapy: Nitisinone is a drug that inhibits the production of HGA. It has been shown to reduce HGA levels and slow tissue damage. However, it needs to be taken under close medical supervision because of potential side effects.
Low-Protein Diet: Since HGA is a byproduct of protein metabolism, reducing protein intake—especially foods rich in tyrosine and phenylalanine—may help decrease HGA production.
Pain Management: OTC pain relievers and anti-inflammatory medications can be used to relieve joint pain and stiffness.
Physical Therapy: Exercise regularly, as it may improve mobility and strengthen muscles, thus reducing strain on affected joints.
Surgical Interventions: Most people with alkaptonuria develop severe osteoarthritis necessitating joint replacement in their old age. Also, some may require heart valve replacement surgery if cardiovascular complications develop.
Although alkaptonuria is not fatal, it severely affects the quality of life. The progressive deterioration of the joints and associated symptoms can make everyday activities difficult, requiring lifestyle changes and medical interventions. The disease may cause premature aging of the joints, requiring walking aids and mobility assistance earlier than expected.
Ongoing research will continue to work on improving the treatment options by focusing on gene therapy and alternative enzyme replacement therapies. However, because of its rarity, the clinical trials and research remain sparse.
As genetic research advances, more hope for better management and possible curative approaches for alkaptonuria exists. Scientists are searching extensively for enzyme replacement therapies and innovative drugs that can target the root cause of the disorder. Being aware and being diagnosed early helps individuals better their condition and ultimately have better long-term health outcomes.
Alkaptonuria is a striking example of how one gene mutation can have widespread effects on the body. Though still a rare and often misunderstood condition, growing awareness and advances in treatment are paving the way for better care. If you or a loved one suspect symptoms of alkaptonuria, it is essential to seek early diagnosis and medical guidance to manage the disease effectively and preserve quality of life.
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Morning walks are a popular part of many older adults’ daily routines. But is walking alone enough to maintain bone strength and prevent osteoporosis as we age?
Walking 30–40 minutes every day is a good habit. However, it may not be enough to maintain bone and muscle strength as we age. A person may walk daily and still struggle to get up from a low chair or maintain balance on an uneven surface. These are important signs of functional strength that deserve as much attention as daily step counts, experts said on World Osteoporosis Day.
Falls are a significant concern among older adults worldwide. A 2022 systematic review and meta-analysis of 104 studies estimated that 26.5% of older adults globally experienced falls. In India, a 2026 analysis of data from the Longitudinal Ageing Study in India found that 11.56% of adults aged 60 and older reported a history of falls. Chronic joint disease was among the factors independently associated with falls.
Also read: Osteoporosis Affects Nearly 20% Of US Women Aged 50+: Why Screening Is Key
Dr. Siddhart Yadav, Senior Consultant, Orthopedics and Joint Replacement Surgery, Apollo Hospitals, Navi Mumbai, told HealthandMe that bone density and muscle mass tend to decline with age.
“In women, bone loss can accelerate after menopause, while men too are at risk of age-related bone loss. When weaker bones are combined with reduced muscle strength and poor balance, even a relatively minor fall can result in a fracture, particularly around the hip or wrist,” he said.
“While women are hit hardest, often assuming household chores are adequate exercise, men are equally vulnerable as muscle mass silently declines after 50. In both, excess weight paired with weak muscle leaves weaker bones exposed to fractures during simple falls,” Dr. Thineshchandar Andiappan, Senior Orthopaedic and Joint Replacement Surgeon, Athulya Geriatric Hospital told HealthandMe.
A casual morning walk alone may not provide enough stimulus to maintain bone density, muscle strength, and balance. Experts recommend combining walking with progressive resistance and strength training. Starting in your 40s can help preserve strength, but it is never too late to begin an appropriate exercise routine.
Along with regular walking, older adults should include simple strength and balance exercises in their routine.
Dr. Siddhart suggested chair sit-to-stands, supported squats, heel raises, and resistance-band exercises to help maintain the strength needed for everyday activities. Light dumbbell exercises for the upper body can also help strengthen the arms, shoulders and other upper-body muscles.
Exercises should be introduced gradually and tailored to individual health and mobility, particularly for people with osteoporosis or a history of fractures.
A 30-40-minute walk is beneficial, but it does not have to be completed in one stretch. If the muscles begin to feel tired, taking a short break of two to three minutes before resuming the walk is reasonable.
Read More: Osteoporosis Drugs Offer New Hope For Back Pain By Blocking Disc Mineralisation: Study
Along with exercise, adequate nutrition supports bone and muscle health. Calcium-rich foods such as milk, curd, paneer, ragi and sesame, together with adequate protein, can help meet nutritional needs. Vitamin D levels should be assessed when clinically indicated.
“Falls in elderly persons happen more often due to instability, muscle weakness, and other reasons. It is very important to address all the issues in addition to the management of osteoporosis for preventing such fractures. The comprehensive treatment will include a good diet, adequate sunlight exposure, in addition to exercises, which must involve weight training and stability-building training,” Dr. V Singaravadivelu, Senior Consultant and Academic Lead, Orthopaedic Surgery, Kauvery Hospital told HealthandMe.
Beef and lamb contain Neu5Gc, a naturally occurring sugar associated with a higher risk of type 2 diabetes in a new study. (Image Credits: iStock)
A sugar naturally found in red meat may help explain why beef and lamb have long been linked to type 2 diabetes, according to a large new study presented at the European Association for the Study of Diabetes’ Annual Meeting in Milan.
Researchers tracked nearly 90,000 adults with no history of diabetes or cancer through NutriNet-Sante, a long-running French health study, according to a release from the European Association for the Study of Diabetes (EASD). Over a median follow-up of 7.2 years, 966 participants developed type 2 diabetes.
The focus was a sugar called N-glycolylneuraminic acid, or Neu5Gc, found mainly in beef and lamb. People with the highest intake of meat-derived Neu5Gc had a 63% higher risk of developing type 2 diabetes than those with the lowest intake, the EASD reported. The risk rose steadily with intake: the second-highest group already carried a 41% higher risk.
“This is a relative risk: people in the top fifth of meat-derived Neu5Gc intake had a 63% higher risk than those in the bottom fifth, after accounting for many other factors,” said lead author Dr. Leopold Fezeu of Universite Sorbonne Paris Nord told Medical News Today. “It does not mean that 63% of high consumers will develop diabetes.”
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Most mammals produce Neu5Gc naturally, but humans lost that ability after an ancient genetic mutation, according to the EASD. The sugar can still enter the body through food and get absorbed into human tissue. Because the body doesn’t recognise Neu5Gc as its own, the immune system may treat it as foreign, producing antibodies against it in a prolonged immune response called xenosialitis, previously linked to cardiovascular disease and cancer.
“Our findings support chronic inflammation as a specific mechanism linking red meat consumption with T2D, partly beyond the amount of red meat a person eats and partly independent of body fat,” Fezeu said.
Not just weight: Notably, obesity accounted for only about 13% of the link between Neu5Gc intake and diabetes risk, the EASD reported, suggesting the sugar’s effects may extend beyond weight gain alone.
Dairy showed no link: Despite also containing Neu5Gc, dairy products showed no association with diabetes risk, likely because cow’s milk contains far smaller amounts than red meat.
When researchers additionally adjusted for total red meat intake, the Neu5Gc-diabetes link weakened and was no longer statistically significant, though it pointed the same direction.
“There may be differences between sources, or other components of red meat may contribute,” Fezeu said, meaning the study can’t fully separate Neu5Gc’s effect from red meat generally.
Since the study is observational, it cannot prove Neu5Gc causes diabetes. Fezeu’s team plans to measure antibodies against Neu5Gc directly and study how it interacts with iron in red meat.
“Future research should explore whether reducing exposure to meat-derived Neu5Gc, for example by favoring poultry or plant-based proteins over beef and lamb... could help prevent T2D,” Fezeu said.
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As we brace ourselves for another bout of winter, we can’t help but feel wary about the changes the dip in temperature brings on our mood and mental well-being. You are not imagining winter depression when you start to feel sudden loss of joy.
Seasonal depression is more than feeling gloomy. You may no longer enjoy the activities you once relished, like listening to music, exercising or meeting friends. This isn’t just another effect of winter. Experts have designated a term for it: anhedonia.
Anhedonia refers to the loss of pleasure or interest in something you once enjoyed. It is one of the symptoms of depression, including seasonal affective disorder (SAD). Unlike sadness, anhedonia can render someone feeling disconnected with or indifferent towards things they once enjoyed.
A person experiencing anhedonia may still participate in activities they enjoy but will no longer reap emotional rewards from it.
“Anhedonia is not the kind of sadness where you’re feeling down but still have moments of enjoyment,” Dr Deeksha Kalra, Associate Consultant, Psychiatry, Artemis Hospital, Gurugram, explained to HealthandMe.
Dr Samant Darshi, Consultant Psychiatrist and Neuromodulation Expert at Yatharth Hospitals, told us, “While sadness entails the state of feeling unhappy about something, anhedonia pertains to the lack of enjoyment.”
Dr Kalra said, during SAD, anhedonia may be experienced during the affected season like winter.
“This can happen at the same time as low mood, but it can also be one of the clearest symptoms. In SAD, these changes are usually present during the affected season and resolve with the resolution of the depressive episode. So anhedonia is about muted pleasure, not just feeling sad,” Dr Kalra explains.
Changes that come with SAD, a type of depressive phase, usually pertains to specific seasons, like mostly winter. Due to less duration of daylight, the body’s internal clock, known as circadian rhythm, may get affected. Along with circadian rhythm, poor diet, irregular sleep pattern and limited physical activity can also contribute to SAD.
This could cause one to feel difficult to initiative activities they enjoy as they no longer feel motivated, affecting the brain reward system.
“Seasonal affective disorder (SAD) causes disturbance of mood, sleep, energy, and motivation. Activities which were pleasurable before become less rewarding because of this. The changes in daylight hours may affect the body clock or the physiological processes related to mood control. The decrease in energy and motivation makes doing the activity even harder and less pleasurable,” said Dr Darshi.
Dr Kalra explains that there are a lot of phases to experiencing ‘enjoyment’. It involves identifying something rewarding, anticipating it, experiencing pleasure and learning from the experience. Depression can affect all these phases, making previously enjoyable activities feel less rewarding.
“Brain networks including the striatum and nucleus accumbens, contribute to the valuation of rewarding experiences and the motivation of behavior. When their responses are dulled and something that was once naturally rewarding may not have the same emotional resonance,” she says.
Also read: Children’s Mental Health Often Goes Unnoticed: Can India’s New School Policy Change That?
Dopamine is a neurotransmitter in the brain responsible for motivation, rewards, learning, and directing behaviour as per goals. When we talk about SAD and anhedonia, dopamine comes into the picture as it is related to motivation and rewards.
Dr Kalra explained, “Dopamine is involved in motivation, reward anticipation, learning and determining the value of pursuing something. That’s why dopamine has been looked at when researchers have investigated anhedonia and low motivation.”
But doctors say that anhedonia is not characterised by shortage of dopamine. According to research, SAD has been reported to affect dopamine signalling, including lower dopamine transporter availability in the striatum during symptomatic depression.
Dr Darshi also emphasises that dopamine is only a part of the process.
He said, “Studies concerning depression and anhedonia indicate that changes in the activity of dopamine result in the decrease in motivation and reward sensitivity. However, anhedonia encompasses many brain processes.”
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Anhedonia makes one indifferent by directly affecting the anticipatory pleasure mechanism. Anticipatory pleasure is the excitement one feels before an event. Consummatory pleasure is the enjoyment experienced while the event is in progress.
“Anhedonia can affect the anticipatory pleasure you feel when you look forward to something and the consummatory pleasure you experience when it actually happens. Someone might know that a favorite meal, holiday or meeting with friends should be enjoyable but feel little excitement beforehand. The pleasure might also feel weaker than expected when the event happens,” Dr Kalra explains.
Everyone with SAD experiences anhedonia in different ways. While some may lose interest and pleasure, others may withdraw socially, sleep excessively, eat more, feeling more tired among other symptoms.
“SAD doesn’t affect everybody in exactly the same way any more than depression is a single biological process. Different people can experience different combinations of changes in mood regulation, circadian rhythms, sleep, appetite and energy and reward processing,” says Dr Kalra.
She also said that multiple symptoms may interact. For example, poor sleep could result into daytime sluggishness, making energetic activities less tempting.
Dr Darshi explained, “Individuals with SAD have different presentations since biology, genetics, circadian rhythm, and psychology are unique for each person. Some individuals have disturbances in reward and motivation, whereas others have sleep disturbances or carbohydrate cravings, or even fatigue. Symptoms might be overlapping and are a reflection of various underlying mechanisms.”
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