Are Microgreens Bad For Kidney Stones? (2024)

Last updated on August 12th, 2023 at 01:53 am

Formation of Kidney Stones | Calcium and Citrate | Oxalate | Vitamin C | Protein

We know patients who suffer from kidney stones disease will have a strict diet on the food selection. But, what about microgreens?

Despite containing stone-forming nutrients, eating microgreens moderately is less likely to cause the formation of kidney stone. The presence of citrate in most microgreens will counterbalance the formation of calcium oxalate, a compound responsible for 80% of all the kidney stones. Also, drinking enough water is another big factor in preventing the stones.

Just like their mature vegetablecounterpart, microgreens (tiny seedlings)containing agreat amount of nutrition. In fact, I have compiled a list of research data hereto prove you the point. I outlined that many microgreens, despite its small size, are containing a surprisedly higher nutrition value compared to their mature counterpart.

That is certainly a piece of good news for those health-centric people to include microgreens in their diet, but not so much for those with kidney related diseases. In particular, the kidney stone.

We have listed the top 5 microgreens for cancer here.

The Formation of Kidney Stones – Which microgreens to avoid?

Kidney stones are formed by an aggregation of small mineral crystals in the kidney. The small crystals eventually developed into bigger salt stones over time [1], which causes the renal blockage and painful experience.

Most of the time, these tiny salt crystals were small enough to pass through kidney tract and urine out of the body naturally [2].

The factor of stones formationis greatly depending on your daily dietary and fluid intake. Learn microgreens for weight loss here.

For instance, researchers have found that dietary with high calcium [3], sodium [4], phosphate [5] and vitamin C [6] were all showed a positive correlation with an increased risk of getting kidney stone. And all these substances were present in most of the common microgreens on the market [7], including the arugula, broccoli, brussel sprout, cabbage, kale, mustard, and radish.

Although there is no scientific evidence linking microgreens to the formation of kidney stone, the presence of high concentration of micro-elements (Iron and Zinc) and macro-elements (Potassium and Calcium) [7] in the microgreens could be one of the risk factors to blame.

Are you in FODMAP diet? Check these microgreens.

Calcium and Citrate in Microgreens – The main cause for 80% stones?

Calcium ions bind to oxalate to form calcium oxalate stone. This compound responsible for 80% of all the kidney stone diseases [8]and it is commonly regarded as the main cause.

Therefore, kidney stone patients are often told to maintain a minimal calcium intake.

One study [7] analyzed over 30 types of common microgreens has found a significant amount of calcium present in the microgreens. The calcium content ranging from the lowest 39mg to the highest 98mg per 100g. To give you an idea, the calcium in milk (1% fat) is 125 mg per 100gaccording to USDA.

Calcium level in microgreens

Top 4 microgreens lowest in calcium content (per 100g):

• Peppercress – 39 mg (81 mg in mature peppercress)
• Radish Ruby – 41 mg (25 mg in mature radish)
• Red Mustard – 47 mg (58 mg in mature yellow mustard)
• Mizuna – 48 mg (115 mg in mature mizuna)

Top 4 microgreens highest in calcium content (per 100g):

• Savoy Cabbage – 98 mg (35 mg in mature savoy cabbage)
• Cauliflower – 94 mg (22 mg in mature cauliflower)
• Purple Kohlrabi – 92 mg (24 mg in mature kohlrabi)
• Rapini – 92 mg (108 mg in mature rapini)

Data according toZ. Xiao et al. / Journal of Food Composition and Analysis 49 (2016) 87–93 [7] and USDA national nutrient database.

From the data above, it showed that microgreen can be a good source of calcium.

Counterbalance by citrate

That being said, most vegetables and fruits (even thoughwith high calcium/oxalate content by itself, such as broccoli and cauliflower) will contain as much citrate which acted as powerful inhibitors to counterbalance the formation of kidney stones [9, 10]. Citrate (or citric acid) is the generic central metabolites that can be found in varieties of greens. One study has further confirmed the presence of a healthy level of citric acid in all four microgreens (beet greens, peppercress, lettuce, wheatgrass)[11]. It also presents in most other commercially available common microgreens, including the Tronchuda cabbage [12] and mung bean [13].

In other words, eating vegetable and microgreens at a moderate intake will less likely to lead to kidney stones.

Remarkably, one study has found an increased risk of stone formation by 35-37% from drinking orange and grape juice [14]. Although the reason remains unclear, it’s believed the high sugar content in these juices caused the excretion of bone calcium, and thereby increases the calcium oxalate formation.

Another popular dietary is using microgreens in Keto diet.

Oxalate (oxalic acid) in Microgreens – The culprit of kidney stone.

We know oxalate is bad for kidney stone patients. Why is that present in plant?

In plants,oxalic acid produced by CO₂fixation. And the acid plays a role in fending off the pest [15]. While in human, It prominently binds to calcium ion to form calcium oxalate — the culprit of kidney stone.

However, due to a lack of scientific literature on this topic, the oxalic acid concentration in many microgreens remains unknown.

Still, oxalate is known to present in most vegetables, fruit, and nuts. For example, high oxalate greens including the rhubarb, sorrel, buckwheat, parsley, broccoli, spinach, beets and more [16]. The concentration varied from one to another, here is a PDF of the oxalate content in some of the common food. Remarkably, you can reduce oxalate in vegetable simply by cooking them [17].

So, what about the oxalate in sprout? Sprout is a younger sibling of microgreens which typically harvested in 3-5 days in oppose to 7-14 days in microgreens. Even though sprout is technically different from microgreens, sprout resembles closely to microgreens in nutritional value.

One study has found the oxalate content in 3-day-old pearl millet is 24-48% lower than their mature counterpart. And the oxalate content of that two pearl millet species (sprout stage) in the study was 27.5 mg/100g and 16.4 mg/100g [18], respectively.

Generally, the oxalate content below50 mg/100g is considered low.

In the other study, tronchudacabbage seedlings have found oxalic acid concentration gradually decreased from day-2 to day-12 upon germination. And the average of oxalic acid content over the course is ~15 mg/100g [12].

Some said vitamin C will induce stone formation…

Interestingly, as vitamin C is first thought to be harmless to kidney stone patients, many studies had reported an increase in urinary oxalate content from the vitamin C intake, which may pose a risk of stone formation [19, 20].

As the debate goes, a recent case study showed the otherwise, wherethere is no kidney stones reported via the vein administration of Vitamin C [21] despite being 8% of the patients had a history of renal stones.

The mechanism remains unclear.

Uric acid stones caused by the high protein content in microgreens?

Unlike calciumoxalate stone, uric acid stone accounts for only about 5-10% of the kidney stone disease [19]. It is usually caused by having too much protein in the diet.

When protein (mostly animal protein) breaks down in your body, byproducts such as the purines, amino acid, uric acid, and other acidic metabolites will acidify the urine, lowering pH, and eventually favors the formation of uric acid stones [20].

Also, having a high protein diet will increase the urinary secretion of calcium, in turn, weaken the bone density [21,22].

Unlike animal protein, most microgreens contain a good amount of citrate and citric acid. These substances act as an alkalinizing agent to compensate for the acidity in urine, and to prevent the stone formation by actively forming a complex with the excess calcium ions [23 24]. On one hand, high amount of potassium found in many common microgreens will help the urinary secretion of citrate [7,25]; On the other, magnesium (in many microgreens) also found to pose a positive effect on inhibiting the stone formation [26].

Therefore,

even if microgreens such as the chicory and lettuce contain as much proteins as their mature counterpart [27], it will not give you the same negative impact as the animal protein. That being said, a moderate intake is advised.

If you have something to share with me, drop your thoughts in the comment section below. By the way, I have compiled nearly all microgreens (more than 100 types of them!) in another articlehere, I am sure you will need it.