What are normal alt levels. Understanding ALT Levels: Normal Range, High Results, and Lowering Strategies
What are normal ALT levels in adolescent males. How do high ALT levels affect liver health. What factors contribute to elevated ALT. How can ALT levels be lowered naturally. What are the implications of revised ALT reference ranges for adolescents.
Revised ALT Reference Range for Adolescent Males
A groundbreaking study conducted in Sydney, Australia has redefined the upper limit of normal for alanine aminotransferase (ALT) levels in adolescent males. The research, published in the December issue of Hepatology, challenges long-standing standards and has significant implications for diagnosing liver conditions in young men.
The study, led by Jacob George, Ph.D., of the University of Sydney, analyzed ALT levels in 439 males aged 12 to 19 years. The findings revealed that the upper limit of normal for ALT should be set at 28 IU/L, substantially lower than the previous standard range of 45 to 55 IU/L.
Key Findings of the ALT Study
- New upper limit of normal ALT: 28 IU/L
- 17% of participants had elevated ALT levels based on the new threshold
- Strong associations found between elevated ALT and:
- HCV antibody positivity
- Overweight and obesity
- Elevated total cholesterol
- Over 90% of adolescents with high ALT had one or more features of metabolic syndrome
Why is this revision important? The researchers argue that the new definition will allow for greater sensitivity in diagnosing early liver injury in adolescent male populations. By identifying those with hepatitis B and C infections and obesity-related liver disease earlier, targeted interventions can be implemented to minimize future health-related morbidity.
Understanding ALT and Its Role in Liver Health
Alanine aminotransferase (ALT) is an enzyme primarily found in liver cells. When liver cells are damaged or die, ALT is released into the bloodstream. Elevated levels of ALT in the blood can indicate liver damage or disease.
What causes ALT levels to rise? Several factors can contribute to elevated ALT levels:
- Viral hepatitis (B and C)
- Obesity and metabolic syndrome
- Excessive alcohol consumption
- Certain medications
- Nonalcoholic fatty liver disease (NAFLD)
Is ALT the only liver enzyme to consider? While ALT is a crucial indicator of liver health, other enzymes such as aspartate aminotransferase (AST) and gamma-glutamyltranspeptidase (GGT) are also important. The study established new upper limits for these enzymes in male adolescents as well:
- AST: 32 IU/L (compared to adult values up to 42 IU/L)
- GGT: 29 IU/L (compared to adult values up to 48 IU/L)
The Impact of Obesity on ALT Levels
One of the most striking findings of the study was the strong association between elevated ALT levels and obesity. The researchers found that overweight or obese adolescents were significantly more likely to have high ALT levels compared to their normal-weight peers.
Obesity and ALT: The Numbers
- 72% of participants with elevated ALT were overweight or obese
- Only 25.1% of participants with normal ALT were overweight or obese
- Odds ratio for elevated ALT in overweight/obese individuals: 6.9 (95% CI: 3.7 to 13.1, P<0.001)
How does obesity contribute to elevated ALT levels? Excess body weight, particularly visceral fat, can lead to fat accumulation in the liver, a condition known as nonalcoholic fatty liver disease (NAFLD). NAFLD can cause inflammation and damage to liver cells, resulting in increased ALT release into the bloodstream.
Viral Hepatitis and ALT Elevations
The study also highlighted the significant impact of viral hepatitis on ALT levels in adolescent males. Hepatitis C virus (HCV) infection, in particular, was strongly associated with elevated ALT levels.
HCV and ALT: Key Statistics
- 57.1% of HCV-positive participants had elevated ALT
- 16.3% of HCV-negative participants had elevated ALT
- Odds ratio for elevated ALT in HCV-positive individuals: 14.6 (95% CI: 3.7 to 57.6)
Why is the relationship between viral hepatitis and ALT important? The strong association between HCV infection and elevated ALT underscores the importance of screening for viral hepatitis in adolescents with abnormal liver enzyme levels. Early detection and treatment of viral hepatitis can prevent long-term liver damage and reduce the risk of complications.
Cholesterol Levels and ALT: An Unexpected Connection
The study revealed an intriguing link between high cholesterol levels and elevated ALT in adolescent males. This finding adds to the growing body of evidence suggesting a complex relationship between lipid metabolism and liver function.
Cholesterol and ALT: The Data
- Odds ratio for elevated ALT in participants with high cholesterol: 3.6 (95% CI: 1.7 to 7.7)
How might high cholesterol contribute to elevated ALT levels? While the exact mechanism is not fully understood, high cholesterol levels may contribute to the development of NAFLD, which in turn can lead to elevated ALT. Additionally, both high cholesterol and elevated ALT may be markers of metabolic dysfunction, reflecting underlying insulin resistance and inflammation.
Natural Strategies to Lower ALT Levels
Given the importance of maintaining healthy ALT levels, many individuals may wonder how to lower their ALT naturally. While medical intervention may be necessary in some cases, several lifestyle modifications can help reduce ALT levels:
- Drink coffee: Regular coffee consumption has been associated with lower ALT levels in numerous studies. The antioxidants and other bioactive compounds in coffee may help protect liver cells from damage.
- Improve your diet: Adopting a healthy, balanced diet rich in fruits, vegetables, whole grains, and lean proteins can help reduce inflammation and support liver health. Avoiding processed foods, saturated fats, and added sugars is also crucial.
- Increase folic acid or folate intake: Folate, a B-vitamin, has been shown to have protective effects on the liver. Consuming folate-rich foods like leafy greens, legumes, and fortified grains may help lower ALT levels.
- Lower your cholesterol: Given the association between high cholesterol and elevated ALT, taking steps to reduce cholesterol levels through diet, exercise, and, if necessary, medication can also help lower ALT.
- Avoid alcohol and smoking: Both alcohol and tobacco can cause liver damage and elevate ALT levels. Abstaining from these substances or reducing their consumption can significantly improve liver health.
Are these natural strategies effective for everyone? While these approaches can be beneficial for many individuals, it’s important to consult with a healthcare provider before making significant lifestyle changes, especially if you have underlying health conditions or are taking medications.
Implications for Public Health and Clinical Practice
The revised ALT reference range for adolescent males has far-reaching implications for both public health initiatives and clinical practice. Understanding these implications is crucial for healthcare providers, policymakers, and researchers working to improve liver health outcomes in young populations.
Key Implications of the New ALT Threshold
- Earlier detection of liver abnormalities in adolescent males
- Potential for more timely interventions to prevent liver disease progression
- Need for updated screening protocols in pediatric and adolescent healthcare
- Increased focus on metabolic health in youth populations
- Opportunity for targeted hepatitis B vaccination programs
How might these findings change clinical practice? Healthcare providers may need to reassess their approach to liver function testing in adolescent males, potentially leading to more frequent screening and earlier interventions for those with elevated ALT levels. This could include lifestyle counseling, weight management programs, and hepatitis screening and vaccination.
Future Directions in ALT Research and Liver Health
The groundbreaking study on ALT levels in adolescent males opens up new avenues for research and raises important questions about liver health in young populations. As our understanding of liver function and disease evolves, several areas warrant further investigation:
Potential Research Directions
- Long-term outcomes of adolescents with elevated ALT levels
- Effectiveness of early interventions in preventing liver disease progression
- Gender differences in ALT reference ranges and liver health
- Impact of environmental factors on ALT levels in youth
- Development of non-invasive biomarkers for early detection of liver disease
What challenges lie ahead in liver health research? One of the main challenges will be conducting large-scale, longitudinal studies to track liver health from adolescence into adulthood. Additionally, researchers will need to develop and validate cost-effective screening tools that can be widely implemented in diverse healthcare settings.
The revised ALT reference range for adolescent males represents a significant step forward in our understanding of liver health in young populations. By providing a more sensitive threshold for detecting liver abnormalities, this research has the potential to improve early diagnosis and intervention strategies for liver disease in adolescents.
As we continue to unravel the complex relationships between ALT levels, obesity, viral hepatitis, and metabolic health, it becomes increasingly clear that a multifaceted approach to liver health is necessary. This includes not only medical interventions but also public health initiatives focused on promoting healthy lifestyles, reducing obesity rates, and increasing awareness of liver disease risk factors among young people.
The findings of this study underscore the importance of regular liver function testing in adolescents, particularly those who are overweight or obese or have other risk factors for liver disease. By identifying and addressing liver abnormalities early, we have the opportunity to prevent the progression of liver disease and improve long-term health outcomes for young people.
As research in this field continues to evolve, it will be crucial for healthcare providers, policymakers, and public health officials to stay informed about the latest developments in liver health and to implement evidence-based strategies for prevention, screening, and treatment. With a concerted effort to prioritize liver health in adolescent populations, we can work towards reducing the burden of liver disease and improving overall health outcomes for future generations.
High Normal ALT Limit Lowered for Male Adolescents
— SYDNEY, Australia — The upper limit of normal for the ALT liver enzyme in adolescent males has been too high, said researchers here.
by
John Gever,
Contributing Writer, MedPage Today
December 5, 2007
SYDNEY, Australia, Dec. 5 — The upper limit of normal for alanine aminotransferase (ALT) in adolescent males has been too high, said researchers here.
The upper limit was calculated at 28 IU/L in 439 males 12 to 19 years old, considerably lower than standard definitions, which are in the 45 to 55 IU/L range, Jacob George, Ph.D., of the University of Sydney, and colleagues, reported in the December issue of Hepatology.
- Explain that the study identified the upper limit of normal for ALT in male youths as 28 IU/liter, considerably lower than current standards.
- Explain that 17% of subjects in the study had elevated ALT by the new definition, which was associated with excess body weight, high blood cholesterol levels, and viral hepatitis infections.
The new upper limit is the 95th percentile for ALT levels in adolescents at the lowest risk for liver disease.
The group found that 17% of those in the overall group, all juvenile offenders, had above-normal ALT.
Strong associations with elevated ALT included HCV antibody positivity, overweight and obesity, and elevated total cholesterol, they found. More than 90% of adolescents with elevated ALT levels had one or more features of the metabolic syndrome.
“There was a strong association for overweight or obesity (72% versus 25.1%; P<0.001) to predict elevated ALT,” they wrote. Multivariate analysis for these factors indicated an odds ratio of 6.9 for elevated ALT with overweight or obesity (95% CI: 3. 7 to 13.1, P<0.001).
“This definition will permit greater sensitivity in diagnosing early liver injury in adolescent male populations,” they wrote. “By identifying those with [hepatitis B and C infection] and obesity-related liver disease, targeted interventions can and should be implemented to minimize future health-related morbidity.”
The researchers also identified new upper limits of normal in male adolescents for two other liver enzymes: 32 IU/L for aspartate aminotransferase (AST), and 29 IU/L for gamma-glutamyltranspeptidase (GGT). Published values for the upper normal limits in adults range up to 42 IU/L for AST and 48 IU/L for GGT.
The 439 adolescents in the New South Wales criminal justice system agreed to participate and did not have serious mental problems or substance withdrawal or disruptive behavior when blood samples were drawn. In addition to liver enzymes, the samples were tested for blood lipids, glucose, and hepatitis B and C antibodies and viral loads.
As expected, participants with HCV infection were at significant risk for elevated ALT relative to HCV-negative participants (57.1% versus 16.3%, P<0.001). This translated into an odds ratio of 14.6 (95% CI: 3.7 to 57.6) for elevated ALT in HCV-positive participants.
When 81 of the participants gave additional blood samples one year later, about 3.7% of those who were initially HCV-negative tested positive.
“Greater education regarding blood-borne viruses, risk factors for transmission, and implementing harm minimization strategies in this population is crucial,” the researchers said.
They also recommended routine hepatitis B vaccination for adolescent offenders, noting that only 30% of the participants showed immunity to HBV. Risk-taking sexual activity and drug-taking behaviors put this population at high risk for HBV infection, they said, though only 4% of participants were HBV positive.
High levels of cholesterol were also significantly associated with above-normal ALT (odds ratio: 3.6, 95% CI: 1.7 to 7.7).
The study was funded by the Australian Research Council, the University of Sydney and industry partners, and the New South Wales Department of Juvenile Justice and Justice Health. No financial disclosures were reported. |
Primary Source
Hepatology
Source Reference: Van der Poorten D, et al “Liver disease in adolescents: a cohort study of high-risk individuals” Hepatology 2007; 46: 1750-58.
Please enable JavaScript to view the comments powered by Disqus.
5 Ways to Lower ALT Levels Naturally
- To lower ALT levels, you can drink coffee, improve your diet, get more folic acid or folate, lower your cholesterol, and avoid alcohol or smoking.
- High ALT levels can indicate a liver problem, as these liver enzymes do not function properly and leak into the bloodstream.
- This article was medically reviewed by Rudolph Bedford, MD, gastroenterologist at Providence Saint John’s Health Center in Santa Monica, CA.
- Visit Insider’s Health Reference library for more advice.
If you have high ALT levels — a liver enzyme known as alanine aminotransferase — it may be due to a liver problem. Here’s what you need to know about these liver enzymes and how to lower your ALT levels naturally.
What is ALT?
ALT is an enzyme in your liver cells that helps convert proteins from the foods you eat into energy. If your liver cells are inflamed or injured, they may leak higher amounts of these enzymes, which causes them to be released into your bloodstream.
Your ALT level can be measured through an ALT blood test. For males, the normal amount ranges from 29 to 33 units per liter (IU/L) of blood. For females, the range is 19 to 25 IU/L.
Some of the common causes of a high ALT level include:
- Nonalcoholic fatty liver disease, an accumulation of extra fat in your liver cells that isn’t caused by drinking alcohol
- Drinking excessive amounts of alcohol, such as more than three drinks a day
- Being obese
- Side effects of over-the-counter pain medications (like Tylenol) or cholesterol-lowering medications (like statins)
- Hepatitis A, B, or C
- Heart failure
Fortunately, an elevated ALT level is usually temporary and doesn’t indicate a serious liver problem.
“If you have an elevated liver enzyme test, step one is to give it some time and repeat it,” says hepatologist Zachary Henry, MD, an associate professor in the Division of Gastroenterology and Hepatology at the University of Virginia. “Sometimes these levels go up and down, and it may have just been a red herring.”
But, if you do have persistently high ALT levels, the following lifestyle changes may help lower them and improve your liver health overall.
1. Drink more coffee
“Coffee is a fascinating drink for the liver,” Henry says. In fact, drinking up to four cups a day can help lower your ALT levels, according to a 2017 review.
A large 2014 study found that both caffeinated and decaffeinated coffee lowered levels of abnormal liver enzymes. Of the 27,793 adult participants, those who drank at least three cups of coffee a day had lower ALT levels than participants who didn’t drink coffee.
One caveat is that you should drink coffee without sugar and cream since these can have a detrimental effect on your liver. “It’s best to drink it black,” Henry says.
2. Improve your diet
Studies have found that eating a healthy, well-balanced diet can help lower your ALT level. After 10 men in Japan ate low-calorie lunches for a month that were high in vegetables and low in animal-based proteins, their ALT levels were lowered by 20.3%, according to the results of a small 2013 study.
There are no specific foods or beverages that will lower your ALT level, Henry says. But a healthy diet is important, especially if the cause of an elevated ALT level is nonalcoholic fatty liver disease.
The American Liver Foundation recommends that you eat more of these foods for a healthier liver:
- Fruits and vegetables
- Lean meats
- Fish containing omega-3 fatty acids, such as salmon and trout
- High-fiber foods like whole-grain breads, rice, and cereal
- Fat-free or low-fat milk and other dairy products
On the other hand, you should avoid eating the following:
- Foods high in sugar, fat, or salt
- Fried foods
- Raw or undercooked shellfish like clams or oysters
- Foods containing partially hydrogenated vegetable oils
3. Get more folic acid
Folic acid is a form of vitamin B-9 found in supplements and in its natural form as folate in some foods. It’s essential for the production, growth, and function of red blood cells.
A folic acid deficiency may lead to a higher ALT level. A 2011 study of 480 participants with mild hypertension found that a daily dose of 800 milligrams of folic acid may help lower ALT levels, especially for men and people with elevated ALT levels.
However, Henry warns that you should always consult with your doctor before taking folic acid or other supplements to make sure there are no perceived health risks. Instead of taking folic acid supplements, he recommends eating foods that are high in folate. These include:
- Leafy, dark green vegetables like spinach, kale, and brussels sprouts
- Beans
- Peanuts
- Sunflower seeds
- Whole grains
- Liver
4. Lower your cholesterol
A large 2018 study suggests that high cholesterol levels are associated with elevated ALT levels.
While lowering your cholesterol level may not necessarily also lower your ALT level, making lifestyle improvements like eating a healthy diet and exercising regularly are still important.
“Patients who have fatty liver disease frequently have comorbid medical conditions like high cholesterol, and we certainly want good control of those conditions because of the increased risk of heart disease,” Henry says.
5. Avoid alcohol and smoking
It’s a well-known fact that drinking alcohol can damage your liver, leading to serious health issues like cirrhosis.
A large 2010 study found that normal ALT levels were elevated by 6% for those who drank about two alcoholic drinks each day, and 10.4% for those who had four drinks daily.
Smoking cigarettes should also be avoided since it can harm your liver in several ways. For example, it produces potentially toxic chemicals that could cause liver inflammation and scarring of your liver tissue. Researchers have found that for people who don’t drink alcohol, smoking may be a significant risk factor for developing nonalcoholic fatty liver disease.
Takeaways
While making these lifestyle changes may help lower your elevated ALT level and improve your health overall, it’s important to see a doctor if the level continues to be high after follow-up ALT tests. Your doctor may recommend additional bloodwork and an ultrasound of your liver, or may refer you to a specialist, to determine why your liver is injured or inflamed.
- 6 ways to lower uric acid levels naturally
- The major causes and risk factors for kidney stones
- The 3 best natural home remedies for kidney stones
- 4 ways to lower your creatinine levels naturally
- How to recognize 3 early signs of diabetes
Laura Goldman
Laura Goldman is a Los Angeles-based freelance writer who specializes in human and animal health topics. She writes about her favorite animals at i Still Love Dogs.
Read moreRead less
Internal Rate of Return, IRR – Alt-Invest
View this article in PDF
Internal Rate of Return (IRR) is one of the most popular indicators in financial analysis. It is used in the evaluation of investment projects and other areas. IRR is used, for example, in bond analysis, where the yield to maturity ratio is calculated as the internal rate of return on cash flows from the buyer of the bond.
IRR definition
Cash flow IRR is the discount rate at which the net present value of this cash flow is zero. Thus, IRR is found as a solution to the variable d of the following equation:
Economic meaning IRR is the maximum value of the cost of capital at which the investment project pays off. When evaluating an investment, the IRR is compared with the required rate of return on invested capital, and if the IRR is higher than the required rate of return, then the project is considered attractive.
For a simple option, when at the beginning of the project there is a significant investment, and then the project brings income:
The dependence of NPV on the discount rate usually looks like this:
Since the discount rate has the strongest effect on future income, and the initial investment either does not depend on it at all or depends very little, the higher the rate, the lower the NPV value, and at some point NPV reaches zero – this will be the internal rate of return.
In the equation above, the rate d is in the power of the period number, so for example, for a ten-year cash flow, we get an equation of power 10, the solution of which cannot be written as a simple formula. In practice, the IRR value is always found by selection, most often the built-in functions of MS Excel are used for this.
Calculating IRR in Excel
There are two functions for calculating IRR in Excel:0010 . The work of these functions is based on the selection of the IRR value by the tangent method. More about this in the video
The IRR function is designed for a cash flow built in increments of a year. If in the financial model the cash flow has a different step, especially if the payments are unevenly distributed, and the step changes from period to period, use the second function – NET INDOH. It has one more parameter – the dates of each payment in the cash flow, which allows you to estimate the IRR for any planning step.
Using the Excel function solves the problem of calculating IRR, but does not relieve the analyst from a number of problems inherent in this indicator.
Problem 1: Unusual Investments
IRR is designed to work when there are large negative values (investments) in the cash flow at the beginning and then a series of positive values. In reality, we see many projects where cash flows look more complicated. In this case, the interpretation of the calculated IRR values also becomes difficult, and in some examples, a situation may arise when the project simultaneously has several IRR values.
Let’s say the cash flow looks like this:
The plot of NPV versus discount rate for this stream will look like this:
There are two values in the region of 5% and 30% when the NPV=0 condition is met, therefore these are the correct solutions for IRR. The IRR calculation functions in Excel have an additional parameter – the initial guess from which the IRR is selected. In this case, depending on the starting position, Excel will calculate the IRR as 5% or as 30%. Obviously, the economic interpretation of this calculation will be very difficult, so for such cash flows in the decision-making process, it is better not to use IRR at all.
Problem 2: Reinvestment
The second problem with using IRR to make decisions is that we change the discount rate during the calculation to reflect the required “normal” rate of return on capital. During the analysis, it is considered that the investor could receive such a return by investing in other projects with a similar level of risk, therefore, he expects the same return from investing in the analyzed project.
But if the discount rate of the project is 15%, and the IRR is set at 25%, then it must be taken into account that when calculating the IRR, it was assumed that any money received from the project could further bring the investor a return of 25%. This is not true. As a result, the choice of investment ideas based on IRR is somewhat skewed towards the approval of shorter projects with high turnover, which, in terms of total income, may not be the best solution.
An alternative to IRR is the selection of projects based on an analysis of their NPV, which is free from all the disadvantages of IRR. In addition, the modified internal rate of return (MIRR) indicator, which provides for the use of a separate rate for expected returns on reinvestment, has gained some popularity.
History of IRR creation
Discounted cash flow approaches have been developed by different authors since the end of 19century. In particular, a number of important publications on this subject were prepared by Eugen von Böhm-Bawerk and Irving Fischer. In The Theory of Interest, Fisher even gave an equation for calculating IRR, but he did not mention the modern name of this term and used it only in the case of comparing two investment opportunities.
The term “internal rate of return” and the exact description of its formula were first introduced by Kenneth Boulding in the article “The Theory of a Single Investment” (Boulding, K. E. “The Theory of a Single Investment”. The Quarterly Journal of Economics 49, issue. 3 (May 1, 1935): 475–94).
At the end of the same year, the indicator was mentioned by John Keynes in “The General Theory of Employment, Interest and Money”, he called it “the marginal efficiency of capital”. Since the book played an important role in the development of economics, it is often referred to as the source of the IRR.
Over the next 20 years, IRR was constantly used in investment valuation, but the term was not the standard, and in a number of books “yield” (yield) was used instead, which is now preserved in bond valuation (the well-known term “yield to maturity”, yield to maturity, YTM is the IRR calculated for the bond).
Around the mid-1960s, the term IRR finally replaced other formulations, and a modern understanding of this indicator has developed.
SEO Alt Text: How to Optimize Images
Joshua Hardwick
Head of Department content at Ahrefs (simply put, I’m responsible for making sure every blog post is AWESOME).
Article statistics
Monthly traffic 38
Referring websites 3
Data from Content Explorer
Shows how many different websites link to this content. Generally, the more sites that link to you, the higher you rank on Google.
Shows the monthly estimated search traffic to this article according to Ahrefs. Actual search traffic (according to Google Analytics) is typically 3-5x higher.
The number of times this article was retweeted on Twitter.
Share this article
Contents
Alt text (alt text) describes an image on a web page. It resides in the HTML code and is usually not displayed on the page itself.
But why is it important then? And how can it be used to improve search engine optimization and user experience?
In this tutorial, you will learn:
- The importance of alt text
- How to add alt text to images
- Why you shouldn’t add alt text to all images in a row
- How to write good alt text
- Examples of good and bad alt text
- How to find and fix problems with alt attributes
Why is alt text important?
Alt text is an important factor for four main reasons.
1. Alt text improves accessibility
Millions of people suffer from visual impairment and may use screen readers to consume online content. Such programs convert the content on the screen, including images, into sound.
Images without alt text create problems for these programs because they do not fully convey the content of the page to the user. Usually programs skip such images or, worse, read out long and useless filenames.
Google talks about the importance of alt text for screen readers in their Beginner’s Guide to Search Engine Optimization.
2. Alt text can improve “topic relevance”
Google examines the words on a page to determine its topic.
For example, if a page mentions Poodles, Labradors, and Retrievers, Google will understand that the page contains information about dog breeds.
How does this relate to images?
The point is that sometimes context is “hidden” in images that Google cannot recognize.
Using alt text helps the search engine “see” these images, and therefore better understand your page and its content.
3. Alt text can improve page rank in Google Images
Google Images is the second largest search engine in the world. It handles 20.45% of all web searches, more than YouTube, Bing, and other search engines combined.
This means that you have the opportunity to drive traffic from Google Images.
Just look at the number of clicks to Ahrefs Blog from Google Images over the past three months:
Google’s John Mueller says alt text is an important part of optimizing for Google Images:
Alt text is extremely useful for Google Images – if you want your images to appear in their search results. Even with lazy loading, you know which image will be loaded, so add this information to it as early as possible and check how it renders.
– John (@JohnMu) September 4, 2018
Google uses it to better understand the topic of the page to which the link leads.
But not all links are text links – some are attached to images.
Google says:
If you do decide to use the image as a link, giving it alt text will help Google learn more about the page you’re linking to . Imagine that you are writing anchor text for a text link.
How to Add Alt Text to Images
Simply add an alt attribute to the
tag in your HTML code.
Image with alt attribute:
alt=“meat and beer pie” >
If you use a modern content management system (CMS), then you can certainly add alt text to it without getting into the HTML code itself.
For example, in WordPress, when you add an image to a page or a specific post, an alt text field appears on the screen:
In other CMS, this is done in a similar way.
Here are instructions for some of the more popular CMSs:
- Adding alt text to images in Squarespace
- Adding alt text to images in Wix
- Adding alt text to images in Shopify
Do I need to add alt text to all images?
No, this is a common misconception.
If the image is intended for decorative purposes and does not contain important information, you should not add alt text to it.
For example, some sites use icons to separate content:
They are just for beauty, so you don’t need to add alt text to them. Such text will only annoy visitors with screen readers without adding any “SEO value”.
The same goes for backgrounds or stock images like this:
Having a “bath and candle” alt text won’t help visually impaired readers, as this information is of no use to them. It would be better if the reader completely ignores this image.
But there is one important point. ..
If the image doesn’t require alt text, then it’s best to add an empty alt attribute. You need to do this because some screen readers will read filenames in the absence of alt text, while most will skip empty alt text.
This is what it should look like:
Learn more from this guide from WebAIM.
How to compose good alt text
Alt text is not quantum physics. Follow the five recommendations below and everything will be fine.
- Be laconic . Long alt text will get on the nerves of readers. Use a minimum of words (if you still cannot do without a long description, use the longdesc attribute).
- Be specific. The main task is to describe the image in words.
- Don’t stuff your alt text with keywords. This is not a place for keywords.
- Do not claim to be an image. No need to start descriptions with “Image. ..” or “Photograph…”. Both Google and screen readers can do this themselves.
- Avoid redundancy. Do not repeat information that is already in the image context. For example, if you have a photo of Steve Jobs on your page, and “Steve Jobs” is written right below it, then you do not need to add this description to the alt text. Google should understand that this is a photo caption.
Also, don’t forget to add alt text to the buttons on the forms you use. Otherwise, readers may miss them, and some users will not be able to properly interact with your site.
Examples of good and bad alt text
Let’s test our understanding of the above rules by looking at some examples.
Bad:
OK :
OK :
Ideal : png” alt=”strawberry cream cheesecake”>
Bad :
OK :
Good :
perfect :
Bad :
OK :
Good :
Ideal :
Notice that the model number is included in the text in the last example. This is a good solution, especially for images on product pages in online stores.
How to find and fix problems with alt attributes
There are many services that can crawl your site and find missing alt attributes; one of them is Site Audit by Ahrefs.
But missing alt text is not necessarily a problem, as not all images require it.
For example, take a look at these links with missing alt attributes:
It’s clear from the titles that they don’t need alt text. These are decorative images, which means we would like readers to skip them.
So instead of scouring your site and tinkering with every missing alt attribute (and there are usually quite a few), it’s more useful to check and improve alt text on pages that already have traffic.
There are two good reasons for this:
- People with visual impairments already read them. 2.4% of US citizens have visual impairment. This is approximately one in 42 people; from which it follows that if 10,000 people visit your page a month, then 240 of them cannot fully consume your content.
- They could potentially receive more traffic. Alt text can help images rank higher in Google Images, leading to more traffic. Even a 1% increase for a page with 10,000 visits per month means 100 additional visitors.
Here’s the sequence:
Step 1: Identify the pages with the most natural traffic
Use Google Analytics, Google Search Console, or Ahrefs’ “Top pages” report in Site Explorer.
Step 2: Check your alt attributes
Install the free Chrome Alt Text Tester extension, open your most visited page and activate the extension.
The extension will display alt text when hovering over an image.
If the alt attribute is missing, the extension will report it.
Check the alt text for multiple images on the page. Soon you will have an idea of where they are optimized well, where they are poorly optimized, and where they are not optimized at all.
For example, it only takes a few seconds to scroll through this article and make sure that all the images in it are well optimized …
…or do a reverse inference for this page on The Mirror: