Uric Acid, Hypertension and Gout

When you think of hypertension and the health conditions associated with it, you probably think about heart attacks and stroke. But high blood pressure can increase risk for gout too. Patients with hypertension and gout often have to take medications for the rest of their lives, but lifestyle changes and supplements may be beneficial to lowering uric acid and improving hypertension and gout.

Hyperuricemia

How it uric acid produced?

Uric acid is a normal byproduct of your body’s processes. Purines are released from both the food you eat and from dying cells ⁽¹⁾. Normally, these purines break down and become uric acid. Uric acid will move through the blood and be filtered out by kidneys and exit the body through urine. If the kidneys aren’t able to eliminate all of the uric acid, there will be elevated levels in the blood, also known as hyperuricemia.

High uric acid levels can affect your health. Uric acid can form solid crystals in joints, which causes gout. (If there’s enough build-up, crystal deposits can form kidney stones or cause kidney failure).

Uric acid levels can be detected through a simple blood test. Healthy uric acid levels are usually under 7.0 mg/dL, but some people may develop gout at lower levels ⁽²⁾.

What causes high uric acid levels?

There are a variety of conditions that can affect the body’s ability to remove uric acid from the blood:

• When kidneys are impaired through kidney disease or damage, they aren’t able to remove purines as well.
• Any condition that causes cells to break down will lead to more purines being released. This means a patient with leukemia, lymphoma, multiple myeloma, hemolytic anemia, sickle cell anemia, or heart failure or a patient undergoing chemotherapy may develop hyperuricemia.
• Eating foods high in purines like liver, red meats, beer, and some seafood may also lead to higher uric acid levels.
• Other medical conditions associated with hyperuricemia include alcohol dependence, preeclampsia, liver disease, psoriasis, hypothyroidism, starvation, malnutrition, and lead poisoning.
• Some medicines such as diuretics, niacin, warfarin, and levodopa, may also affect uric acid levels. ⁽²⁾

Hypertension

Hypertension is high blood pressure. When the blood is flowing through arteries, the force of the blood pressing against the blood vessel walls is higher than normal.  Hypertension is classified into two groups:

• One is primary or essential hypertension. This develops gradually and is the most common.
• The other form is secondary hypertension, which is caused by some underlying condition. If the underlying condition is treated, hypertension will go away. ⁽³⁾

For blood pressure to stay normal, the kidneys need to work to maintain fluid balance. Hormones like angiotensin need to be functioning to be able to narrow blood vessels and control kidneys. Additionally, blood vessels need to be functioning properly. ⁽³⁾ This means kidney problems, adrenal gland tumors, thyroid problems, and congenital blood vessel defects can result in secondary hypertension. Some medicines like birth control pills, decongestants, over-the-counter pain relievers, and some prescription medicines can also raise blood pressure. ⁽⁴⁾

Although anyone can develop hypertension, some people have a higher risk:

• Currently, only 2-3% of hypertensive patients are considered to have genetic factors causing their disease.
• Risk factors like age, race, and lifestyle are more common.
• Americans over 60 years old have a higher risk, and it increases with age.
• There are growing numbers of young people with hypertension as well, potentially because of the rise of obesity. Being overweight or obese means you need more blood to get oxygen to your tissues. With more tissue, you need more blood moving through your vessels, and this leads to more pressure on your blood vessel walls.
• Hypertension is more commonly seen in African American adults than Caucasian or Hispanic Americans. ⁽³⁾
• High sodium intake, heavy alcohol drinking, and lack of physical activity are thought to be environmental risk factors. ⁽³⁾ 
• Smoking or chewing tobacco raises your blood pressure, and the chemicals in the tobacco also hurt your artery walls and narrow your arteries.
• Stress can also temporarily increase blood pressure. ⁽⁴⁾

It is important to take high blood pressure seriously because it can damage your body. Hypertension can cause the arteries to become harder and thicker, which is arteriosclerosis. This can lead to a heart attack or stroke. Your heart has to work harder, which can eventually result in heart failure. Weak, narrow blood vessels can result in various parts of the body not working well, such as your kidneys, eyes, and brain. ⁽⁴⁾

How do hyperuricemia and hypertension relate?

In research studies, there seems to be an association between serum uric acid levels and blood pressure. Using a rat model, scientists induced hyperuricemia. Two weeks later, blood pressure increased in proportion to the elevated uric acid. ⁽⁵⁾ This relationship between hyperuricemia and hypertension is consistent across gender, race, and age, after adjusting for lifestyle factors like smoking, drinking, and obesity. Increased risk for hypertension appears to be related to uric acid levels. ⁽⁶⁾ High uric acid levels, even in children and young adults, are associated with hypertension. ⁽⁵⁾

Researchers are investigating how this happens:

• One possibility is that uric acid enters smooth muscle cells and activates the renin-angiotensin system. This could damage the kidneys and lead to sodium retention and increased blood pressure.
• Another possibility is that smooth muscle cells will produce more angiotensin II in the presence of uric acid and stimulate oxidative stress pathways.⁽⁶⁾

Activating the renin-angiotensin system occurs quickly, but it can also be controlled. This is especially important for younger populations to prevent permanent future hypertension. ⁽⁵⁾ Because of how uric acid affects the body, lowering uric acid may improve hypertension as well.⁽⁶⁾

How does Gout form?

When serum uric acid levels are too high, crystals can form in joints and cause gout. There are four stages used to classify gout:

1. The first is asymptomatic hyperuricemia. Uric acid levels are above 6.0 mg/dL, but the patient doesn’t have symptoms of gout. By monitoring uric acid levels and making diet and lifestyle changes, the patients may not experience gout symptoms for years.
2. The second stage is an acute gout attack. The uric acid crystals deposited in joints activate. This causes intense pain and joint swelling, which can last for days. Even though the pain will go away on its own, it is a good idea to visit a doctor, because gout attacks will likely happen again.
3. Intercritical gout is the stage between gout attacks. Although the patient isn’t experiencing adverse symptoms, uric acid crystals are continuing to accumulate, which can cause more gout attacks in the future.
4. The last stage is chronic tophaceous gout, where it becomes chronic arthritis. The inflammatory process can result in harming the bone and cartilage and may even affect the kidneys. Usually, patients receiving medical care do not reach this stage. ⁽⁷⁾

For the majority of people, gout is first found in the big toe and nearly all patients with gout experience it there at some time. Other common joints affected by gout are:

• the instep
• ankle
• heel
• knee
• Achilles tendon
• wrist
• finger, and
• elbow. ⁽⁷⁾

The joint will have sudden and intense pain, stiffness, swelling, redness, and tenderness. ⁽⁷⁾

Risk factors for gout include hyperuricemia, family history, older age, and obesity. People with other medical conditions such as hypertension, heart disease, diabetes, joint injury, and kidney disease, may also be at higher risk for developing gout. ⁽⁸⁾

Diagnosing gout requires an additional test to testing uric acid levels; your doctor will test your joint fluid to find uric acid crystals. ⁽²⁾

Natural Ways to Reduce Uric Acid

Uric acid is a risk factor for gout, and it is often seen with hypertension. ^(8,9) Patients often ask for medicines to treat hyperuricemia, but these medications often need to be taken for a long time and may have serious side effects.⁽⁹⁾ You should talk to your doctor about managing hyperuricemia, hypertension, and gout, but some of the changes suggested may be fairly simple:

Regular Exercise

We all know that regular exercise is important, and it is can help people with hyperuricemia. Regular, light exercise can improve the quality of life for people with high uric acid. A study among elderly Chinese women found daily exercise was inversely related to the prevalence of hyperuricemia. ⁽⁹⁾ Many organizations encourage people to exercise at moderate intensity 150 minutes per week or 30 minutes a day for 5 for more days per week. Some people may have difficulty achieving this amount of exercise due to busyness, but a research study found that patients with hyperuricemia exercising half that amount (15 minutes per day, 5 times a week) also reduced the mortality risks associated with high uric acid. ⁽⁹⁾

Some people may point out that uric acid can increase during exercise, but this depends on how intense the exercise is. Light exercise, like brisk walking, won’t raise uric acid levels as much as heavy exercise. Overall, evidence suggests that exercise may directly impact serum uric acid levels, in addition to improving cardiovascular strength. ⁽⁹⁾ For patients who already have gout, regular exercise is also encouraged. ⁽¹⁰⁾

Diet

Changing your diet can affect your uric acid. Some foods have more purines, which can lead to more uric acid in their body:

• People with gout often will avoid eating too much red meat, organ meat, and shellfish because of the high amount of purines. ⁽⁸⁾
• Limiting alcohol, especially beer, can also help with controlling uric acid levels and blood pressure. ^(8,3)
• Hyperuricemia and hypertension have also been associated with fructose consumption. ⁽⁵⁾
• A high-fructose diet can increase uric acid, so avoiding large amounts of desserts, processed foods, soft drinks, and juices may help with managing hyperuricemia. ⁽⁸⁾

If you have hypertension, you may already be aware of how dietary changes can be helpful, but it may also improve gout flare-ups. The DASH (Dietary Approaches to Stop Hypertension) diet involves eating more whole grains, fruits, vegetables, and low-fat dairy products and limiting red meat, sweets, and saturated fats. In a study where people were either on the DASH diet or a typical American diet, people on the DASH diet had lower uric acid. The people who originally had hyperuricemia had the largest decreases in uric acid. More research is being done to better understand how sodium intake affects gout and hypertension, but the DASH diet may be helpful for gout patients too. ⁽¹¹⁾

Having a healthy body weight is beneficial for gout and hypertension. Someone who is obese is four times more likely to develop gout than someone with ideal body weight. ⁽¹²⁾ Talk to your doctor before beginning a weight loss plan. Crash diets and high-protein diets can increase uric acid levels in the body, so a doctor or nutritionist can direct you to an appropriate diet plan. ⁽¹²⁾

Supplements

Your doctor may recommend taking a Vitamin C supplement. ⁽¹²⁾ In animal models, Vitamin C inhibits the production of uric acid. Researchers have also suggested that Vitamin C helps improve the kidneys clear uric acid. Additionally, due to its antioxidant properties, it helps reduce damage by free radicals, so there is less uric acid produced.

Studies in people have found that vitamin C intake is associated with a lower risk for developing gout. ⁽¹³⁾ By reducing the amount of uric acid in the blood, fewer crystals will form in the joints. ⁽¹⁴⁾ Patients on hemodialysis may also benefit from vitamin C supplements. A study found that taking a supplement improved serum uric acid levels. This is especially important because end-stage renal disease patients often have a vitamin C deficiency. ⁽¹⁵⁾ The recommended dietary allowance is 90 mg/day for men and 75 mg/day for women, but the research studies have found benefits using doses of 500 mg/day. At these levels, there are few side effects. Talk to your doctor before taking supplements, because taking more than 2000 mg/day can result in serious side effects. ⁽¹³⁾

Chinese Herbs

Researchers are looking at how Chinese herbal prescriptions may be beneficial for managing high uric acid. Medications may be included in a hyperuricemia management plan, but many of these have side effects.  In a meta-analysis, Chinese medicinal herbs and traditional Western medicine approaches reduced uric acid to similar levels, but the Chinese medicinal herbs had fewer adverse reactions:⁽¹⁶⁾

• Dried longan seed extract and green tea polyphenols are just a couple of the compounds scientists are investigating. ⁽¹⁷⁾ Herbal prescriptions usually have multiple herbs, so more research is being done to understand the active ingredients. ⁽¹⁶⁾ Because of the multiple herbs used, the active ingredients are able to work synergistically and will contain condition-improving ingredients. This means the symptoms like redness, swelling, heat, and pain from a gout attack are being managed while uric acid levels are being lowered through aiding kidney and artery function. ⁽¹⁸⁾
• Oligonol ® is made from lychee fruit. In a study with 6 adult males, taking Oligonol ® led to lower serum and urine uric acid levels. ⁽¹⁹⁾
• Ermiao wan is considered to get rid of heat and dampness in TCM. In mice, Ermiao wan lowered uric acid levels for both normal and hyperuricemic mice. ⁽²⁰⁾
• Burdock root has been used for hypertension, gout, and other inflammatory disorders and it appears to have free radical scavenging activity. ⁽²¹⁾
• Terminalia chebula and Terminalia bellercia have been studied for their anti-inflammatory and antioxidant properties. A randomized clinical trial found that the patients who received T. chebula or T. bellerica every day for treatment had lower serum uric acid levels, with no serious adverse events and are being further studied for their ability to help gout patients. ⁽²²⁾

Although studies have generally shown fewer side effects with herbal supplements taken for gout, you should always talk to your doctor before beginning a new supplement, fitness program, or diet.