Page 48 - Today's Dietitian (February 2020)

CPE Monthly

tablets or a placebo. The results of the seven groups; five received one of the difficult to assess the most beneficial
study suggest that, along with a heart- doses of garlic, another group received garlic preparations related to cancer
healthy diet, garlic powder tablets may metformin, and a final group took a pla- prevention. However, the promising
provide cholesterol-lowering effects. The cebo. Compared with the placebo group, results of studies that used AGE, garlic
total cholesterol and LDL cholesterol every group that received a dose of garlic oil, and raw garlic suggest benefits from
levels of the treatment group decreased had significantly lower fasting blood consuming garlic in any form.
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by 11.5% and 13.8%, respectively, com- sugar and HbA1c after 24 weeks. The
pared with those in the placebo group garlic tablets, especially at doses greater Immune System
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after 12 weeks. than or equal to 900 mg, were compa- Garlic also may have immunomodu-
A study by Seo and colleagues assessed rable to metformin in reducing blood latory effects and anti-inflammatory
the efficacy of AGE extract on lipid levels sugar and HbA1c. These studies offer activities, such as the inhibition of the
in 30 women in their 50s. It showed a sig- very promising support for the use of proliferation of proinflammatory cyto-
nificant decrease in LDL levels in women garlic in diabetes management. kines and stimulation of immune cells.
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who consumed 80 mg AGE, those who Specifically, garlic oil may prevent the
exercised and took AGE, or those who Cancer activity of Th1 lymphocytes that regu-
just exercised and took a placebo, com- Due to the antioxidant effects of garlic late the proinflammatory response and
pared with those in the group who didn’t compounds, especially SAC, it appears enhance the ability of Th2 lymphocytes
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exercise and took a placebo. that garlic also may protect against to produce an anti-inflammatory pro-
These results suggest a possible pro- cancer. Dong and colleagues investi- cess. Liu and colleagues analyzed the
tective effect of certain garlic supple- gated a mechanism through which aged effects of garlic oil on Th1 and Th2 lym-
ments against elevated lipid levels that black garlic extract may thwart cancer phocytes in rats and suggested that the
may put individuals at risk of heart cell production by performing a study on response was dose-dependent; larger
disease. However, more clinical stud- in vitro colon cancer cells. Their results doses of garlic oil were more effective at
ies are needed to assess the most effec- suggest a promising anticancer mecha- inducing an anti-inflammatory response
tive duration, type, and dose of garlic nism, indicating that aged black garlic from Th2 cells over a two-week period.
preparations. extract induces cell death in cancer cells Interestingly, smaller doses of the oil
by blocking a specific pathway that sig- had the opposite effect and stimulated
Diabetes nals cancer cell growth. Th1 cell responses.
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In some studies, researchers have dem- Additional research on the effects of Other studies clarify the role of garlic
onstrated that garlic supplements can garlic on cancer has analyzed the impact in immune response. For example, a
lower blood sugar levels in individu- of garlic oil preparations. Specifically, study designed by Nantz and colleagues
als with type 2 diabetes. Ashraf and garlic oil appears to protect against liver analyzed the ability of AGE to influ-
colleagues recruited 60 patients with cancer that develops from exposure to ence immune cell proliferation. They
fasting blood sugar between 100 and the environmental carcinogen N-nitroso- recruited 120 participants and divided
130 mg/dL and divided them into two diethylamine, found in cheese, processed them into two groups, one that received
groups. Each group received 500 mg of meats, some alcohol, and agricultural 2.56 g AGE per day and one that received
metformin two times per day and either chemicals. Researchers gave rats doses of placebos. After 45 days, they analyzed
900 mg of garlic tablets or a placebo. the carcinogen over 20 weeks to induce blood samples and found that those
After analyzing fasting blood sugar nodules on their livers. At the same time, who took AGE had significantly more
levels at 24 weeks, the authors concluded they gave a continuous administration of proliferation of two specific immune
that garlic tablets contributed to a sig- garlic oil to one group of rats and equal cells compared with those who didn’t.
nificant 3.12% reduction in these levels doses of corn oil to the other group. The The researchers hypothesized that AGE
for those in the experimental group rats in the garlic oil group had a signifi- may improve the capability of certain
compared with the control group par- cantly lower number of nodules on their immune cells to become activated, lead-
ticipants. The garlic tablets generally livers compared with their counterparts. 6 ing to a stronger immune reponse. 24
were well tolerated, and only one partici- This cancer-protective effect of garlic oil Strengthening the immune system,
pant reported stomach discomfort. The may be due to the induction of phase II especially in those susceptible to infec-
researchers acknowledge that the mech- liver enzymes that block the development tion or illness, is a possible benefit of
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anism through which garlic tablets can of cancerous nodules. garlic preparations. Madineh and col-
lower blood sugar isn’t well known, but Finally, even raw garlic may protect leagues performed a short trial with 94
that garlic appears to promote the secre- against cancer by upregulating genes patients admitted to the ICU to analyze
tion of insulin. that promote cell death. Charron and the effect of taking a 400 mg garlic tablet
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Another study by Ashraf and col- colleagues found that just a single meal daily for six days on inflammatory blood
leagues analyzed the effect of garlic tab- with 5 g (the equivalent of one clove) markers and the occurrence of infec-
lets in doses of 300, 600, 900, 1,200, and of raw, crushed garlic activated genes tions. In comparison with those who
1,500 mg per day on both fasting blood related to apoptosis and destruction took a placebo, patients who received the
sugar and hemoglobin A1c (HbA1c) in of cancer cells. The different types garlic supplements had a significantly
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210 individuals with type 2 diabetes. The and doses used in studies that analyze lower body temperature. However, there
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researchers divided the participants into the protective effects of garlic make it were no other significant differences
48 TODAY’S DIETITIAN • FEBRUARY 2020